big
39) How many moles are there in 2.00 kg of copper? The atomic weight of copper is 63.5 g/mol and its density is 8.90 g/cm3. A) 15.3 B) 31.5 C) 51.3 D) 53.1
: B
4) In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Which one of the following statements about the gas is correct? A) The gas must absorb heat from its surroundings. B) The gas must release heat to its surroundings. C) The pressure of the gas also stays constant. D) The process is adiabatic. E) It is impossible to predict on the basis of this data.
: B
40) An ideal gas has a pressure of 2.5 atm, a volume of 1.0 L at a temperature of 30°C. How many molecules are there in this gas? (R = 8.31 J/mol ∙ K,1.00 atm = 101 kPa, NA = 6.022 × 1023) A) 6.1 × 1023 B) 6.0 × 1022 C) 2.4 × 1022 D) 2.3 × 1023
: B
41) If 50 g of lead (of specific heat 0.11 kcal/kg ∙ C°) at 100°C is put into 75 g of water (of specific heat 1.0 kcal/kg ∙ C°) at 0°C. What is the final temperature of the mixture? A) 2.0°C B) 6.8°C C) 25°C D) 50°C
: B
42) A lab assistant pours 330 g of water at 45°C into an 855-g aluminum container that is at an initial temperature of 10°C. The specific heat of aluminum is and that of water is 4186 J/kg ∙ K. What is the final temperature of the system, assuming no heat is exchanged with the surroundings? A) 28°C B) 32°C C) 31°C D) 33°C E) 35°C
: B
44) A certain automobile tire has a volume of 0.0185 m3. If the absolute (or total) pressure in the tire is 500 kPa and the temperature is 298 K, how many molecules are there inside the tire? (R = 8.31 J/mol ∙ K, NA = 6.022 x 1023 molecules/mol) A) 2.25 × 1023 molecules B) 2.25 × 1024 molecules C) 3.25 × 1023 molecules D) 3.25 × 1024 molecules E) 3.25 × 1025 molecules
: B
46) A lab assistant drops a 400.0-g piece of metal at 100.0°C into a 100.0-g aluminum cup containing 500.0 g of water at In a few minutes, she measures the final temperature of the system to be 40.0°C. What is the specific heat of the 400.0-g piece of metal, assuming that no significant heat is exchanged with the surroundings? The specific heat of this aluminum is 900.0 J/kg ∙ K and that of water is 4186 J/kg ∙ K. A) 1900 J/kg ∙ K B) 2270 J/kg ∙ K C) 3300 J/kg ∙ K D) 3800 J/kg ∙ K E) 4280 J/kg ∙ K
: B
46) Your lungs hold 4.2 L of air at a temperature of 27°C and a pressure of 101.3 kPa. How many moles of air do your lungs hold? (R = 8.31 J/mol ∙ K) A) 0.15 moles B) 0.17 moles C) 0.19 moles D) 0.21 moles E) 0.23 moles
: B
5) At what, if any, temperature are the numerical readings on the Fahrenheit and Celsius scales the same? A) -30° B) -40° C) -50° D) -60° E) They can never read the same because they are based on different zeroes.
: B
60) Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10.0° C. In the first run, a 200-g cube of frozen alcohol, at the melting point, is added to 300 g of water at 20.0°C in a styrofoam container. When thermal equilibrium is reached, the alcohol-water solution is at a temperature of 5.0°C. In the second run, an identical cube of alcohol is added to 500 g of water at 20.0°C and the temperature at thermal equilibrium is 10.0°C. The specific heat capacity of water is 4190 J/kg ∙ K. Assume no heat is exchanged with the styrofoam container and the surroundings. What is the heat of fusion of the alcohol? A) 5.5 × 104 J/kg B) 6.3 × 104 J/kg C) 7.1 × 104 J/kg D) 7.9 × 104 J/kg E) 8.7 × 104 J/kg
: B
63) The "hot shot" heat engine operating between 40°C and 380°C has an efficiency that is 60% of that of an ideal Carnot engine operating between the same temperatures. If the "hot shot" engine absorbs heat at a rate of 60 kW, at what rate does it exhaust heat? A) 36 kW B) 41 kW C) 57 kW D) 60 kW
: B
66) A sealed container holds 0.020 moles of ideal nitrogen (N2) gas, at a pressure of 1.5 atm and a temperature of 290 K. The atomic mass of nitrogen is 14.0 g/mol. What is the average translational kinetic energy of a nitrogen molecule? The Boltzmann constant is 1.38 × 10-23 J/K. A) 4.0 ×1021 J B) 6.0 ×1021 J C) 8.0 ×1021 J D) 10 ×1021 J E) 12 ×1021 J
: B
69) Suppose that the Department of Energy develops a new reversible engine that has a coefficient of performance (COP) of 4.0 when operated as a refrigerator and a COP of 5.0 when operated as a heat pump. What is its thermal efficiency when operated as a heat engine doing work? A) 10% B) 20% C) 25% D) 45% E) 80%
: B
69) The molecular weight of nitrogen, N2, is 28 g/mol. What is the rms speed of nitrogen molecules in a cooler at 8.0°C? The Boltzmann constant is 1.38 × 10-23 J/K and NA = 6.022 × 1023 molecules/mol. A) 450 m/s B) 500 m/s C) 550 m/s D) 600 m/s E) 650 m/s
: B
7) A machine part consists of 0.10 kg of iron (of specific heat 470 J/kg ∙ K ) and 0.16 kg of copper (of specific heat 390 J/kg ∙ K). How much heat must be added to the gear to raise its temperature from 18°C to 53°C? A) 910 J B) 3800 J C) 4000 J D) 4400 J
: B
76) An ideal Carnot air conditioner operates between an indoor temperature of 20°C and an outdoor temperature of 39°C. How much energy does it use to remove 2000 J of heat from the interior of the house? A) 105 J B) 130 J C) 780 J D) 520 J E) 340 J
: B
77) The thermal conductivity of aluminum is twice that of brass. Two rods (one aluminum and the other brass) of the same length and cross-sectional area are joined together end to end. The free end of the brass rod is maintained at 0°C and the free end of the aluminum rod is maintained at 200°C. If no heat escapes from the sides of the rods, what is the temperature at the place where the two rods are joined together? A) 76°C B) 133°C C) 148°C D) 155°C
: B
78) If an ideal gas molecule has a speed of 0.50 km/s at 20°C, what is its speed at 80°C? A) 500 m/s B) 550 m/s C) 1000 m/s D) 2000 m/s
: B
85) What is the net power that a person with surface area of 1.20 m2 radiates if his emissivity is 0.895, his skin temperature is 27°C, and he is in a room that is at a temperature of 17°C? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 60.3 W B) 62.6 W C) 65.7 W D) 68.4 W E) 64.8 W
: B
89) Two identical objects are placed in a room with a temperature of 20°C. Object A has a temperature of 50°C, while object B has a temperature of 90°C. What is the ratio of the net power emitted by object B to the power emitted by object A? A) 1.7 B) 2.8 C) 81 D) 17 E) 21
: B
9) The weather outside is frightful. The temperature is -22°F. What is the corresponding temperature in the Celsius scale? A) -35°C B) -30°C C) -22°C D) -20°C E) -12°C
: B
93) A container of ideal gas at STP undergoes an isothermal expansion and its entropy changes by 3.7 J/K. How much work does it do? A) 0.0 J B) 1.0 × 103 J C) -1.0 × 103 J D) 1.4 × 103 J E) -1.4 × 103 J
: B
10) A mole of diatomic oxygen molecules and a mole of diatomic nitrogen molecules are at STP. Which statements are true about these molecules? (There could be more than one correct choice.) A) Both gases have the same average molecular speeds. B) Both gases have the same number of molecules. C) Both gases have the same average kinetic energy per molecule. D) Both gases have the same average momentum per molecule.
: B, C
30) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. In the figure, Pa = Pc = 240 kPa, Vb = Vc = 40 L, Va = 15 L, and Pb = 400 kPa. How much heat is gained by the gas in this a→b→c→a process? A) 1000 J B) 1500 J C) 2000 J D) 2500 J E) 3000 J
: C
48) A person is walking outdoors on a cold day when the temperature is -20°C. He is breathing at the rate of 16 breaths per minute, and each time he breathes in he inhales 0.0050 m3 of air. At what rate does he lose heat from breathing if the air in his lungs is heated to body temperature (37°C) before it is exhaled? The specific heat of air is 1020 J/kg ∙ K and the density of air is 1.29 kg/m3. A) 60 W B) 90 W C) 100 W D) 150 W E) 300 W
: C
52) A person makes iced tea by adding ice to 1.8 kg of hot tea, initially at 80°C. How many kilograms of ice, initially at 0°C, are required to bring the mixture to 10°C? The specific heat of water (and tea) is 4186 J/kg ∙ K, and the latent heat of fusion of ice is 3.34 × 105 J/kg. A) 1.0 kg B) 1.2 kg C) 1.4 kg D) 1.7 kg
: C
1) At room temperature, a typical person loses energy to the surroundings at the rate of 62 W. If this energy loss has to be made up by an equivalent food intake, how many kilocalories (food calories) does this person need to consume every day just to make up this heat loss? (1 cal = 4.186 J) A) 1000 kcal B) 1100 kcal C) 1300 kcal D) 1500 kcal E) 1600 kcal
: C
1) Which two temperature changes are equivalent? A) 1 K = 1 F° B) 1 F° = 1 C° C) 1 C° = 1 K D) none of the above
: C
12) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a clockwise sense around the enclosed area, as shown on the figure, then the change of internal energy over the full cycle A) is positive. B) is negative. C) is zero. D) cannot be determined from the information given.
: C
12) A sample of an ideal gas is heated and its Kelvin temperature doubles. If the root-mean-square speed of its molecules was originally v, what is the new root-mean-square speed? A) 4v B) 2v C) v D) v/ E) v/4
: C
13) The absolute temperature of an ideal gas is directly proportional to which of the following quantities? A) the average speed of its molecules B) the average momentum of its molecules C) the average kinetic energy of its molecules D) the mass of its molecules E) It is proportional to all of the above quantities.
: C
15) Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, the average molecular kinetic energy of oxygen molecules, compared to that of hydrogen molecules, A) is greater. B) is less. C) is the same. D) cannot be determined without knowing the pressure and volume.
: C
16) A quantity of mercury occupies 400.0 cm3 at 0°C. What volume will it occupy when heated to 50°C? Mercury has a volume expansion coefficient of 180 × 10-6 K-1. A) 450 cm3 B) 409.7 cm3 C) 403.6 cm3 D) 401.8 cm3
: C
16) By what primary heat transfer mechanism does the sun warm the earth? A) convection B) conduction C) radiation D) All of the above processes are equally important in combination.
: C
17) During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the work done by the gas in the process? A) 0 J B) 5.0 J C) -5.0 J D) -10 J
: C
18) The volume coefficient of thermal expansion for gasoline is 950 × 10-6 K-1. By how many cubic centimeters does the volume of 1.00 L of gasoline change when the temperature rises from 30°C to 50°C? A) 6.0 cm3 B) 12 cm3 C) 19 cm3 D) 37 cm3
: C
19) In an adiabatic compression, 200 J of work is done on a gas. What is the change in internal (thermal) energy of the gas during this compression? A) 0 J B) 100 J C) 200 J D) -200 J
: C
2) Express -40°C in °F. A) -72°F B) -54°F C) -40°F D) 4.4°F
: C
20) A mercury thermometer has a glass bulb of interior volume 0.100 cm3 at 10°C. The glass capillary tube above the bulb has an inner cross-sectional area of 0.012 mm2. The coefficient of volume expansion of mercury is 1.8 × 10-4 K-1. If the expansion of the glass is negligible, how much will the mercury rise in the capillary tube when the temperature rises from 5°C to 35°C if the bulb was full at 5°C? A) 0.45 mm B) 4.5 mm C) 45 mm D) 45 cm
: C
20) An ideal gas undergoes an adiabatic process while doing 25 J of work. What is the change in the internal (thermal) energy of the gas? A) 0 J B) 25 J C) -25 J D) 50 J E) -50 J
: C
20) Which of the following is a false statement? A) Entropy is a quantitative measure of disorder. B) The total entropy change in one cycle of a Carnot engine is zero. C) The entropy of an isolated system must be conserved (it remains constant). D) Entropy can be measured in units of J/K.
: C
21) An ideal gas undergoes an isothermal expansion. During this process, its entropy A) decreases. B) remains unchanged. C) increases. D) cannot be predicted from the data given.
: C
22) During an isochoric process, the internal (thermal) energy of a gas decreases by 50 J. How much heat is added to the gas during this process? A) 0 J B) 50 J C) -50 J D) 25 J E) -25 J
: C
24) An external heat source supplies heat to a system at a rate of 187 W as the system does work at a rate of 131 W. At what rate is the internal (thermal) energy of the system changing? A) -56 W B) 320 W C) 56 W D) 190 W E) -320 W
: C
4) A temperature change of 20 C° corresponds to a Fahrenheit temperature change of A) 68 F°. B) 11 F°. C) 36 F°. D) 18 F°.
: C
48) A weather balloon containing 2.0 m3 of hydrogen gas rises from a location at which the temperature is 22°C and the pressure is 101 kPa to a location where the temperature is -39°C and the pressure is 20 kPa. If the balloon is free to expand so that the pressure of the gas inside is equal to the ambient pressure, what is the new volume of the balloon? A) 4.0 m3 B) 6.0 m3 C) 8.0 m3 D) 10 m3 E) 12 m3
: C
5) The coefficient of linear expansion for aluminum is 1.8 × 10-6 K-1. What is its coefficient of volume expansion? A) 9.0 × 10-6 K-1 B) 5.8 × 10-18 K-1 C) 5.4 × 10-6 K-1 D) 3.6 × 10-6 K-1 E) 0.60 × 10-6 K-1
: C
50) A heat engine having the maximum possible efficiency has an efficiency of 25% when operating between two heat reservoirs. If the temperature of the cold reservoir is 300 K, what is the temperature of the hot reservoir? A) 350 K B) 375 K C) 400 K D) 450 K E) 500 K
: C
51) When 50 g of a certain material at 100°C is mixed with 100 g of water at 0°C, the final temperature is 40°C. What is the specific heat of the material? The specific heat of water is 1.00 kcal/kg ∙ C°. A) 0.33 kcal/kg ∙ C° B) 0.75 kcal/kg ∙ C° C) 1.3 kcal/kg ∙ C° D) 7.5 kcal/kg ∙ C°
: C
52) A gas-filled vertical cylinder, closed at the bottom end, is fitted at the top with a piston that can move freely. The mass of the piston is 10.0 kg, and the initial height of the piston above the bottom of the cylinder is 25 cm. A mass of 8.0 kg is placed on the piston. What is the resulting height of the piston, assuming that the temperature of the ideal gas is kept constant? A) 12 cm B) 13 cm C) 14 cm D) 15 cm E) 16 cm
: C
52) For a certain ideal Carnot engine, the hot reservoir is 35 C° higher than the cold reservoir. If this engine is to have an efficiency of 20%, what must be the temperature of the hot reservoir? A) 70.0 K B) 140 K C) 175 K D) 210 K E) 245 K
: C
53) A quantity of an ideal gas is kept in a rigid container of constant volume. If the gas is originally at a temperature of 19°C, at what temperature will the pressure of the gas double from its original value? A) 91°C B) 38°C C) 311°C D) 273°C E) 122°C
: C
56) Two ideal Carnot heat engines have the same efficiency. One operates between 5.0 × 102 K and 3.0 × 102 K, and the other between 4.0 × 102 K and some lower temperature. What is the lower temperature? A) 200 K B) 220 K C) 240 K D) 260 K E) 280 K
: C
6) If 150 kcal of heat raises the temperature of 2.0 kg of a material by 400 F°, what is the specific heat capacity of the material? A) 1.35 kcal/kg ∙ C° B) 0.75 kcal/kg ∙ C° C) 0.34 kcal/kg ∙ C° D) 0.19 kcal/kg ∙ C°
: C
6) Two metal spheres are made of the same material and have the same diameter, but one is solid and the other is hollow. If their temperature is increased by the same amount, A) the solid sphere becomes bigger than the hollow one. B) the hollow sphere becomes bigger than the solid one. C) the two spheres remain of equal size. D) the solid sphere becomes denser and the hollow one less dense. E) the solid sphere becomes less dense and the hollow one denser.
: C
61) Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10° C. In the first run, a 200-g cube of frozen alcohol, at the melting point, is added to 300 g of water at 20°C in a styrofoam container. When thermal equilibrium is reached, the alcohol-water solution is at a temperature of 5°C. In the second run, an identical cube of alcohol is added to 500 g of water at 20°C and the temperature at thermal equilibrium is 10°C. The specific heat capacity of water is 4190 J/kg ∙ K. Assume no heat is exchanged with the styrofoam container and the surroundings. What is the specific heat capacity of the alcohol? A) 1700 J/kg ∙ K B) 1900 J/kg ∙ K C) 2100 J/kg ∙ K D) 2300 J/kg ∙ K E) 2500 J/kg ∙ K
: C
70) At what temperature is the rms speed of hydrogen molecules, H2, which have a molecular weight of 2.02 g/mole, equal to 2.0 km/s? The Boltzmann constant is 1.38 × 10-23 J/K and NA = 6.022 × 1023 molecules/mol. A) 17°C B) 34°C C) 51°C D) 68°C E) 72°C
: C
8) A solid cylindrical bar conducts heat at a rate of 25 W from a hot to a cold reservoir under steady state conditions. If both the length and the diameter of this bar are doubled, the rate at which it will conduct heat between these reservoirs will be A) 200 W B) 100 W C) 50 W D) 25 W E) 12.5 W
: C
8) An aluminum electric tea kettle with a mass of 500 g is heated with a 500-W heating coil. How long will it take to heat up 1.0 kg of water from 18°C to 98°C in the tea kettle? The specific heat of aluminum is 900 J/kg ∙ K and that of water is 4186 J/kg ∙ K. A) 5.0 minutes B) 7.0 minutes C) 12 minutes D) 15 minutes E) 18 minutes
: C
81) A sphere of surface area 1.25 m2 and emissivity 1.0 is at a temperature of 100°C. At what rate does it radiate heat into empty space? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 7.1 W B) 0.71 mW C) 1.4 kW D) 9.9 mW E) 3.7 W
: C
83) How much power does a sphere with a radius of 10 cm radiate into empty space if is has an emissivity of 1.0 and is kept at a temperature of 400 K? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 60 W B) 70 W C) 180 W D) 210 W E) 360 W
: C
86) When 1.0 kg of steam at 100°C condenses to water at 100°C, what is the change in entropy of the steam? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) zero B) 6.1 × 103 J/K C) -6.1 × 103 J/K D) 22.6 × 105 J/K E) -22.6 × 105 J/K
: C
9) An ideal gas is held in a container of volume V at pressure p. The rms speed of a gas molecule under these conditions is v. If now the volume and pressure are changed to 2V and 2p, the rms speed of a molecule will be A) v/2 B) v C) 2v D) 4v E) v/4
: C
9) Two metal rods are to be used to conduct heat from a region at 100°C to a region at 0°C as shown in the figure. The rods can be placed in parallel, as shown on the left, or in series, as on the right. When steady state flow is established, the heat conducted in the series arrangement is A) greater than the heat conducted with the rods in parallel. B) the same as the heat conducted with the rods in parallel. C) less than the heat conducted with the rods in parallel.
: C
90) In an electric furnace used for refining steel, the temperature is monitored by measuring the radiant power emitted through a small hole in the wall of the furnace, of area 0.5 cm2. This hole acts like a perfect blackbody radiator having the same temperature as the interior of the furnace. If the temperature of the furnace (and therefore of the hole) is to be maintained at 1650°C, how much power will the hole radiate? A) 20 W B) 30 W C) 40 W D) 50 W
: C
92) When 0.50 kg of water at 0°C freezes, what is the change in entropy of the water? The latent heat of fusion of water is 33,400 J/kg. A) 0 J/K B) 610 J/K C) -610 J/K D) -17,000 J/K E) 17,000 J/K
: C
both of them experience the same size gain or loss of heat. D) It is impossible to tell without knowing the masses. E) It is impossible to tell without knowing the volumes.
: C
18) A Carnot cycle consists of A) two adiabats and two isobars. B) two isobars and two isotherms. C) four isotherms. D) two adiabats and two isotherms. E) four adiabats.
: D
23) The coefficient of linear expansion of copper is 17 × 10-6 K-1. A block of copper 30 cm wide, 45 cm long, and 10 cm thick is heated from 0°C to 100°C What is the change in the volume of the block? A) 2.3 × 10-5 m3 B) 4.6 × 10-5 m3 C) 5.2 × 10-5 m3 D) 6.9 × 10-5 m3 E) 14 × 10-5 m3
: D
4) Consider a flat steel plate with a hole through its center as shown in the figure. When the temperature of the plate is increased, the hole will A) expand only if it takes up more than half the plate's surface area. B) contract if it takes up less than half the plate's surface area. C) always contract as the plate expands into it. D) always expand with the plate. E) remain the same size as the plate expands around it.
: D
43) A balloon originally has a volume of 1.0 m3 when the gas in it is at 20°C and under a pressure of 1.0 atm. As it rises in the earth's atmosphere, its volume expands. What will be its new volume if its final temperature and pressure are -40°C and 0.10 atm? A) 2.0 m3 B) 4.0 m3 C) 6.0 m3 D) 8.0 m3
: D
5) A 4.0-kg aluminum block is originally at 10°C. If 160 kJ of heat is added to the block, what is its final temperature? The specific heat capacity of aluminum is 910 J/kg ∙ K. A) 24°C B) 34°C C) 44°C D) 54°C
: D
56) A 40.0-g block of ice at -15.00°C is dropped into a calorimeter (of negligible heat capacity) containing water at 15.00°C. When equilibrium is reached, the final temperature is 8.00°C. How much water did the calorimeter contain initially? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 302 g B) 345 g C) 405 g D) 546 g E) 634 g
: D
6) Oxygen condenses into a liquid at approximately 90 K. What temperature, in degrees Fahrenheit, does this correspond to? A) -193°F B) -217°F C) -265°F D) -297°F
: D
70) During each cycle of operation, a refrigerator absorbs 230 J of heat from the freezer and expels 356 J of heat to the room. How much work input is required in each cycle? A) 712 J B) 586 J C) 460 J D) 126 J
: D
84) A blacksmith is flattening a steel plate having dimensions 10 cm × 15 cm × 1 mm. He has heated the plate to 900 K. If the emissivity of the plate is 0.75, at what rate does it lose energy by radiation? Ignore any heat exchange with the surroundings. (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 360 W B) 760 W C) 790 W D) 850 W E) 880 W
: D
11) On a cold day, a piece of metal feels much colder to the touch than a piece of wood. This is due to the difference in which one of the following physical properties of these materials? A) density B) specific heat C) emissivity D) thermal conductivity E) mass
: D
11) The root-mean-square speed of the molecules of an ideal gas is v. The gas is now slowly compressed to one-half its original volume with no change in temperature. What is the root-mean-square speed of the molecules now? A) 4v B) 2v C) v/ D) v E) v/2
: D
12) A steel bridge is 1000 m long at -20°C in winter. What is the change in length when the temperature rises to 40°C in summer? The average coefficient of linear expansion of this steel is 11 × 10-6 K-1. A) 0.33 m B) 0.44 m C) 0.55 m D) 0.66 m
: D
13) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a clockwise sense around the enclosed area, as shown on the figure, then the magnitude of the enclosed area represents A) the heat that flows out of the gas. B) the work done on the gas. C) the heat added to the gas. D) the work done by the gas.
: D
14) An object having a fixed emissivity of 0.725 radiates heat at a rate of 10 W when it is at an absolute temperature T. If its temperature is doubled to 2T, at what rate will it now radiate? A) 20 W B) 40 W C) 80 W D) 160 W E) 320 W
: D
2) The temperature in your classroom is closest to A) 68 K. B) 68°C. C) 50°C. D) 295 K.
: D
22) Suppose that a rigid aluminum wire were to be strung out in a loop that just fits snugly around the equator (assuming a perfectly spherical Earth with a radius of 6.37 × 106 m). If the temperature of the wire is increased by 0.50°C, and the increase in length is distributed equally over the entire length, how far off the ground will the wire loop be if it remained centered on the earth? The coefficient of linear expansion of aluminum is 24 × 10-6 K-1. A) 7.6 mm B) 76 mm C) 76 cm D) 76 m E) 760 m
: D
28) The coefficient of linear expansion of copper is 17 × 10-6 K-1 and that of steel is 12 × 10-6 K-1. At 12°C a steel rod has a diameter of 2.540 cm and a copper pipe has a diameter of 2.536 cm. Which one of the following quantities is closest to the temperature to which the copper pipe must be heated in order for the unheated steel rod to fit snugly in the copper pipe? A) 53°C B) 81°C C) 93°C D) 105°C E) 143°C
: D
3) The temperature changes from 35°F during the night to 75°F during the day. What is the temperature change on the Celsius scale? A) 72 C° B) 40 C° C) 32 C° D) 22 C°
: D
4) Which one of the following quantities is the smallest unit of heat energy? A) calorie B) kilocalorie C) Btu D) joule
: D
41) A car starts out when the air temperature is 288 K and the absolute (total) air pressure in the tires is 500 kPa. After driving a while, the temperature of the air in the tires increases to 298 K. What is the pressure in the tires at that point, assuming their volume does not change? A) 129 kPa B) 483 kPa C) 507 kPa D) 517 kPa E) 532 kPa
: D
42) An ideal gas occupies 6.00 × 102 cm3 at 20°C. At what temperature will it occupy 1.20 × 103 cm3 if the pressure is held constant? A) 10°C B) 40°C C) 100°C D) 313°C
: D
44) A camper is about to drink his morning coffee. He pours 400 grams of coffee, initially at 75°C into a 250-g aluminum cup, initially at 16°C. What is the equilibrium temperature of the coffee-cup system, assuming no heat is lost to the surroundings? The specific heat of aluminum is 900 J/kg ∙ K, and the specific heat of coffee is essentially the same as that of water, which is 4186 J/kg ∙ K. A) 45°C B) 62°C C) 65°C D) 68°C E) 71°C
: D
45) On a cold day, you take in 4.2 L of air into your lungs at a temperature of 0°C. If you hold your breath until the temperature of the air in your lungs reaches 37°C, what is the volume of the air in your lungs at that point, assuming the pressure does not change? A) 4.2 L B) 4.4 L C) 4.6 L D) 4.8 L E) 5.0 L
: D
49) A heat engine having the maximum possible efficiency has an efficiency of 35.0% when operating between two heat reservoirs. If the temperature of the hot reservoir is 700 K, what is the temperature of the cold reservoir? A) 200 K B) 245 K C) 350 K D) 455 K E) 600 K
: D
54) A 35-g block of ice at -14°C is dropped into a calorimeter (of negligible heat capacity) containing 400 g of water at 0°C. When the system reaches equilibrium, how much ice is left in the calorimeter? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 32 g B) 33 g C) 35 g D) 38 g E) 41 g
: D
58) A 24.0-L tank contains ideal helium gas at 27°C and a pressure of 22.0 atm. How many moles of gas are in the tank? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 238 mol B) 138 mol C) 17.5 mol D) 21.4 mol E) 76.0 mol
: D
58) An 920-g piece of iron at 100°C is dropped into a calorimeter of negligible heat capacity containing 50 g of ice at 0°C and 92 g of water, also at 0°C. What is the final temperature of the system? The specific heat of iron is 448 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 0°C B) 11°C C) 14°C D) 24°C E) 32°C
: D
60) A sealed container holds 0.020 moles of ideal nitrogen (N2) gas, at a pressure of 1.5 atm and a temperature of 290 K. The atomic mass of nitrogen is 14.0 g/mol. How many molecules of nitrogen are in the container? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 1.5 × 1021 mol B) 3.0 × 1021 mol C) 6.0 × 1021 mol D) 1.2 × 1022 mol E) 2.4 × 1022 mol
: D
68) A concrete wall of a cold storage room measures 3.0 m high, 5.0 m wide, and 20 cm thick. The inside wall is to be covered by a layer of wood in order to reduce the rate of heat flow through the wall by 90 percent. The inner surface of the wooden wall is maintained at -10°C and the outer surface of the concrete wall is at 20°C. The thermal conductivities of concrete and wood are 0.80 W/m ∙ K (concrete) and 0.040 W/m ∙ K (wood). What is the temperature difference across the layer of wood? A) 24 C° B) 25 C° C) 26 C° D) 27 C° E) 28 C°
: D
69) A concrete wall of a cold storage room measures 3.0 m high, 5.0 m wide, and 20 cm thick. The inside wall is to be covered by a layer of wood in order to reduce the rate of heat flow through the wall by 90 percent. The inner surface of the wooden wall is maintained at -10°C and the outer surface of the concrete wall is at 20°C. The thermal conductivities of concrete and wood are 0.80 W/m ∙ K (concrete) and 0.040 W/m ∙ K (wood). What should be the thickness of the layer of wood? A) 60 mm B) 70 mm C) 80 mm D) 90 mm E) 100 mm
: D
74) An air conditioner with a coefficient of performance of 3.50 uses 30.0 kW of power to operate. What power is it discharging to the outdoors? A) 30.0 kW B) 75.0 kW C) 105 kW D) 135 kW E) 210 kW
: D
74) An oxygen molecule, O2, falls in a vacuum. From what height must it fall so that its translational kinetic energy at the bottom of its fall equals the average translational kinetic energy of an oxygen molecule at 920 K? The mass of one O2 molecule is 5.312 × 10-26 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. Neglect air resistance and assume that g remains constant at 9.8 m/s2 throughout the fall of the molecule. A) 49 km B) 12 km C) 24 km D) 37 km E) 5.2 km
: D
78) A window glass that is 0.5 cm thick has dimensions of 3 m by 1.5 m. The thermal conductivity of this glass is 0.8 W/m ∙ K. If the outside surface of the glass is at -10°C and the inside surface is at 20°C, how much heat flows through the window in every hour? A) 50 MJ B) 60 MJ C) 70 MJ D) 80 MJ
: D
both of them experience the same size temperature change. D) It is impossible to tell without knowing the masses. E) It is impossible to tell without knowing the volumes.
: D
17) A fixed container holds oxygen and helium gases at the same temperature. Which of the following statements are correct? (There could be more than one correct choice.) A) The oxygen molecules have the greater average kinetic energy. B) The helium molecules have the greater average kinetic energy. C) The oxygen molecules have the greater speed. D) The helium molecules have the greater speed. E) The helium molecules have the same average kinetic as the oxygen molecules.
: D, E
21) How much heat must be removed from 456 g of water at 25.0°C to change it into ice at -10.0°C? The specific heat of ice is 2090 J/kg ∙ K, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat of water is 4186 J/kg ∙ K. A) 105 kJ B) 153 kJ C) 57.3 kJ D) 47.7 kJ E) 210 kJ
: E
26) The coefficient of linear expansion of aluminum is 24.0 × 10-6 K-1, and the density of aluminum at 0°C is 2.70 × 103 kg/m3. What is the density of aluminum at 300°C? A) 3.93 × 103 kg/m3 B) 2.73 × 103 kg/m3 C) 2.70 × 103 kg/m3 D) 2.67 × 103 kg/m3 E) 2.64 × 103 kg/m3
: E
47) A 20.0-L pressure vessel holds 2.00 mol of oxygen at 30°C. What is the pressure inside the vessel? (R = 8.31 J/mol ∙ K) A) 101 Pa B) 101 kPa C) 1.01 MPa D) 2.52 MPa E) 252 kPa
: E
80) In an experiment to measure the thermal conductivity of a certain material, a slab of material 10.0 mm thick separates a steam chamber from a block of ice with a square cross-section with dimensions 8.00 cm × 8.00 cm. After 5.00 min of running the experiment, 64.0 g of ice have melted. What is the thermal conductivity of this material? The latent heat of fusion of water is 33.5 × 104 J/kg, the latent heat of vaporization of water is 2.256 × 106 J/kg, and both the ice and water are under 1.00 atm of pressure. A) 0.130 W/m ∙ K B) 0.250 W/m ∙ K C) 0.440 W/m ∙ K D) 0.620 W/m ∙ K E) 1.12 W/m ∙ K
: E
88) A giant star radiates energy at the rate of 3.0 × 1030 W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star?(σ = 5.67 × 10-8 W/m2 ∙ K4) A) 7.8 × 1010 m B) 8.7 × 1010 m C) 1.4 × 1010 m D) 1.9 × 1011 m E) 2.3 × 1011 m
: E
10) A 5.00-g lead BB moving at 44.0 m/s penetrates a wood block and comes to rest inside the block. If half of its kinetic energy is absorbed by the BB, what is the change in the temperature of the BB? The specific heat of lead is 128 J/kg ∙ K. A) 0.940 K B) 1.10 K C) 1.26 K D) 2.78 K E) 3.78 K
: E
15) If the absolute temperature of an object is tripled, the thermal power radiated by this object (assuming that its emissivity and size are not affected by the temperature change) will A) increase by a factor of 3. B) increase by a factor of 9. C) increase by a factor of 18. D) increase by a factor of 27. E) increase by a factor of 81.
: E
15) Which one of the following is a true statement? A) The second law of thermodynamics is a consequence of the first law of thermodynamics. B) It is possible for heat to flow spontaneously from a hot body to a cold one or from a cold one to a hot one, depending on whether or not the process is reversible or irreversible. C) It is not possible to convert work entirely into heat. D) It is impossible to transfer heat from a cooler to a hotter body. E) All of these statements are false.
: E
19) An important feature of the Carnot cycle is that A) its efficiency can be 100%. B) its efficiency depends only on the absolute temperature of the hot reservoir used. C) its efficiency is determined by the temperatures of the hot and cold reservoirs between which it works and by the properties of the working substance used, and on nothing else. D) it is an example of an irreversible process that can be analyzed exactly without approximations. E) no engine can be more efficient than a Carnot engine operating between the same two temperatures.
: E
2) A person running in place on an exercise machine for 10 min uses up 17 kcal (food calories). Another person exercises by repeatedly lifting two 2.5-kg weights a distance of 50 cm. How many repetitions of this exercise are equivalent to 10 minutes of running in place? Assume that the person uses negligible energy in letting down the weights after each lift. (1 cal = 4.186 J) A) 730 B) 1450 C) 1500 D) 2200 E) 2900
: E
24) If you add 1.33 MJ of heat to 500 g of water at 50°C in a sealed container, what is the final temperature of the steam? The latent heat of vaporization of water is 22.6 × 105 J/kg, the specific heat of steam is 2010 J/kg ∙ K, and the specific heat of water is 4186 J/kg ∙ K. A) 100°C B) 112°C C) 123°C D) 147°C E) 195°C
: E
27) A metal has a latent heat of fusion of 2.32 × 104 J/kg, a specific heat of 128 J/kg ∙ K, and a melting point of 228°C. A 30-g pellet of this metal at 16°C hits a solid wall and comes to a complete stop. What would the speed of the pellet have to be in order for it to melt completely when it hits the wall, assuming that all of its kinetic energy is transformed into heat within the pellet? A) 207 m/s B) 215 m/s C) 232 m/s D) 273 m/s E) 317 m/s
: E
31) A 40.0-L container is divided into two equal parts by a rubber membrane. One half of the container has 1.50 moles of an ideal monatomic gas at 250 K, and the other half is a vacuum. The container is well insulated, so there is no exchange of heat with the surroundings. The membrane breaks, and eventually the gas reaches a new equilibrium condition occupying the entire volume. What is the final temperature of the gas? A) 100 K B) 125 K C) 157 K D) 180 K E) 250 K
: E
4) How much heat is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? The specific heat of lead is 128 J/kg ∙ K. A) 725 J B) 576 J C) 145 J D) 217 J E) 288 J
: E
5) Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are given the same amount of heat. If the temperature of Object 1 changes by an amount ΔT, the change in temperature of Object 2 will be A) ΔT. B) ΔT. C) ΔT. D) 6ΔT. E) 12ΔT.
: E
6) Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are heated from the same initial temperature, T0, to the same final temperature Tf. During this process, if Object 1 absorbs heat Q, the amount of heat absorbed by Object 2 will be A) 12Q. B) 6Q. C) Q. D) Q. E) Q.
: E
66) A heat-conducting rod that is wrapped in insulation is constructed with a 0.15-m length of alloy A and a 0.40-m length of alloy B, joined end-to-end. Both pieces have cross-sectional areas of 0.0020 m2. The thermal conductivity of alloy B is known to be 1.8 times as great as that for alloy A. The end of the rod in alloy A is maintained at a temperature of 10°C, and the other end of the rod is maintained at an unknown temperature. When steady state flow has been established, the temperature at the junction of the alloys is measured to be 40° C, and the rate of heat flow in the rod is measured at 56 W. What is the thermal conductivity of alloy A? A) 120 W/m ∙ K B) 125 W/m ∙ K C) 130 W/m ∙ K D) 135 W/m ∙ K E) 140 W/m ∙ K
: E
67) The rms speed of a certain sample of carbon dioxide molecules, with a molecular weight of 44.0 g/mole, is 396 m/s. What is the rms speed of water vapor molecules, with a molecular weight of 18.0 g/mol, at the same temperature as the carbon dioxide? A) 253 m/s B) 387 m/s C) 421 m/s D) 506 m/s E) 619 m/s
: E
71) A glass tea kettle containing 500 g of water is on the stove. The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 1.5 mm thick. At a certain moment, the temperature of the water is 75°C, and it is rising at the rate of 3 C° per minute. What is the temperature of the outside surface of the bottom of the tea kettle? Neglect the heat capacity of the kettle, and assume that the inner surface of the kettle is at the same temperature as the water inside. The thermal conductivity of glass is 0.840 W/m ∙ K and the specific heat of water is 4186 J/kg ∙ K. A) 39°C B) 92°C C) 120°C D) 86°C E) 77°C
: E
72) A 400-g stainless steel tea kettle containing 500 g of water is on the stove. The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 2.0 mm thick. At a certain moment, the temperature of the water is 75°C, and it is rising at the rate of 3.0 C° per minute. What is the difference in temperature between the inside and the outside of the bottom of the tea kettle? Assume that the inner surface of the kettle is at the same temperature as the water inside. The thermal conductivity of stainless steel is 16.3 W/m ∙ K, the specific heat of the steel is 448 J/kg ∙ K, and the specific heat of water is 4186 J/kg . K. A) 2.2 C° B) 1.5 C° C) 1.1 C° D) 0.50 C° E) 0.15 C°
: E
75) Two metal rods, one silver and the other gold, are attached to each other end-to-end. The free end of the silver rod is immersed in a steam chamber at 100°C, and the free end of the gold rod in an ice water bath at 0°C. The rods are both 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and their surroundings, except at the ends. What is the temperature at the point where the two rods are in contact with one another? The thermal conductivity of silver is 417 W/m ∙ K, and that of gold is 291 W/m ∙ K. A) 39°C B) 41°C C) 47°C D) 53°C E) 59°C
: E
77) During each cycle, the compressor in a certain ideal Carnot refrigerator performs 480 J of work to remove 150 J of heat from the interior of the refrigerator. How much heat do the coils behind the refrigerator discharge into the kitchen each cycle? A) 110 J B) 150 J C) 330 J D) 480 J E) 630 J
: E
8) Nitrogen boils at -196°C. What is the corresponding temperature in the Fahrenheit scale? A) -315°F B) -196°F C) -346°F D) -290°F E) -321°F
: E
82) The cylindrical filament in a light bulb has a diameter of 0.050 mm, an emissivity of 1.0, and a temperature of 3000°C. How long should the filament be in order to radiate 60 W of power? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 11 cm B) 9.4 cm C) 8.6 cm D) 7.2 cm E) 5.9 cm
: E
22) When water at 0°C freezes, the entropy of the water A) increases. B) decreases. C) remains constant. D) could either increase or decrease it depends on other factors
:B
The lift on an airplane wing is an application of
A) Bernoulli's principle
You slam on the brakes of your car in a panic, and skid a certain distance on a straight, level road. If you had been traveling twice as fast, what distance would the car have skidded, under the same conditions?
A) It would have skidded 4 times farther.
A truck has four times the mass of a car and is moving with twice the speed of the car. If Kt and Kc refer to the kinetic energies of truck and car respectively, it is correct to say that
A) Kt = 16Kc.
On a cold winter day, you turn up the thermostat in your house. Assume that your house is well sealed and that no air enters or leaves the house. When the air temperature in your house rises a short while later, what statement is correct regarding the air pressure?
A) The air pressure is higher at the higher temperature.
The flow of water emerging from a hole in a container is best described in terms of
A) Torricelli's law.
The type of heat transfer that occurs between the radiator of a car and the atmosphere, when the car is in motion, is principally
A) convective
The type of heat transfer that occurs between warm food and the air in the room is principally
A) convective
The point in the phase diagram where the vapor pressure curve ends is called the
A) critical point
The heat required to change a substance from the solid to the liquid state is referred to as the
A) heat of fusion
For an object that travels at a fixed speed along a circular path, the acceleration of the object is
A) larger in magnitude the smaller the radius of the circle.
When a gas expands adiabatically,
A) the internal energy of the gas decreases.
A monatomic ideal gas is compressed isothermically to one-third of its initial volume. The resulting pressure will be
A) three times as large as the initial value.
A simple pendulum, consisting of a mass m and a string of length L, swings upward, making an angle θ with the vertical. The work done by the tension force is
A) zero
Above the velocity-versus-time graph for a basketball player traveling up and down the court in a straight line path. Find the displacement of the player for each of the segments A, B, C, and D.
A, 4m; B, 6m ; C, 8m; D, 0m
Four waves are described by the following expressions, where distances are measured in meters and times in seconds. I y = 0.12cos(3x-21t) II y = 0.15sin(6x+42t) III y = 0.13 cos(6x +21t) IV y = -0.23 sin(3x - 42t)
All of them have the same period
Consider three drinking glasses. All three have the same area base, and all three are filled to the same depth with water. Glass A is cylindrical. Glass B is wider at the top than at the bottom, and so holds more water than A. Glass C is narrower at the top than at the bottom, and so holds less water than A. Which glass has the greatest liquid pressure at the bottom?
All three have equal non-zero pressure at the bottom
heat of fusion
Amount of energy required to change a substance from the solid phase to the liquid phase.
Refer to the Figure above. The components of vectors A and B are
Ax = Acos90, Bx = -Bcos60, Ay = Acos90, By = Bcos30
For an ideal monatomic gas
B) Cp > Cv
A boat loaded with rocks is floating in a swimming pool. If the rocks are thrown into the pool, the water level in the pool, after the rocks have settled to the bottom,
B) Falls
Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity.
B) It is moving in a circle.
King Kong falls from the top of the Empire State Building, through the air (air friction is present), to the ground below. How does his kinetic energy (K) just before striking the ground compare to his potential energy (U) at the top of the building?
B) K is less than U.
The hydraulic lift is an application of
B) Pascal's principle.
Two identical samples of a monatomic gas are initially at pressure P and occupy volume V. You perform two experiments which will both lead to the gas samples being compressed to final volumes one-third as large as their initial volumes. In one of the experiments you make the gas undergo an isothermal compression. In the second you make the gas undergo an adiabatic compression. It is correct to say that:
B) The adiabatic compression leads to a higher final pressure than the isothermal compression and the gas does not exchange heat with its surroundings.
In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. Select the true statement from among the following:
B) The gas must release heat to its surroundings.
The type of heat transfer that occurs between a stove and a pot placed on it is
B) conductive
Imagine that the metal head of a hammer is loose. In order to get the hammerhead tight again you should
B) drop the hammer with the handle end down.
A monatomic ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be
B) equal to the initial value.
A liquid boils when its vapor pressure
B) equals the external pressure.
An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the most work?
B) if the pressure increases in proportion to the volume least amount - adiabatically
You ride on an elevator that is moving with constant downward acceleration while standing on a bathroom scale. The reading on the scale is
B) less than your true weight, mg.
A constant force is applied to an object that causes a certain displacement. If the angle between the force and the displacement is 135°, the work done by this force is
B) negative
When you blow some air above a paper strip, the paper rises. This is because
B) the air above the paper moves faster and the pressure is lower.
Consider a plot of the displacement (x) vs. applied force (F) for an ideal elastic spring. The slope of the curve would be
B) the reciprocal of the spring constant.
A thermally isolated system consists of a hot piece of aluminum and a cold piece of copper. The aluminum and the copper are in thermal contact. The specific heat of aluminum is more than double that of copper. Which object experiences the greater amount of heat transfer during the time it takes the system to reach thermal equilibrium? - Both experience the same magnitude of heat transfer. - The aluminum experiences the greater magnitude of heat transfer. - The copper experiences the greater magnitude of heat transfer.
Both experience the same magnitude of heat transfer.
Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat?
Buoyant force is the same in both.
A roller coaster car (mass = M) is on a track that forms a circular loop (radius = r) in the vertical plane. If the car is to just maintain contact with the track at the top of the loop, what is the minimum value for its speed at that point?
C) (rg)1/2
The ratio of the final kinetic energy to the initial kinetic energy of an object is one half. If the initial velocity of the object is 10 m/s, what is the final velocity?
C) 7.1 m/s
For water at 2 degrees
C) Cp < Cv
When atmospheric pressure changes, what happens to the absolute pressure at the bottom of a pool?
C) It increases by the same amount.
Bernoulli's principle is a statement of the
C) conservation of energy
A monatomic ideal gas is compressed adiabatically to one-third of its initial volume. The resulting pressure will be
C) more than three times as large as the initial value.
The process whereby heat flows in the absence of any medium is referred to as
C) radiation
The type of heat transfer that occurs between a heating lamp and the food that it is keeping warm is
C) radiative
A golfer misjudges a putt and leaves her ball way short, the ball going only one-third of the way to the hole. If the speed of the ball leaving the putter in the first case was v0 and the force of resistance due to the grass remains the same, what speed should she have given to the ball to make the original putt?
C) v0
Coefficient of Performance (COP)
COP= Qh/W
For water at 2°C, what is the relationship between Cp and Cv?
Cp < Cv
For an ideal monatomic gas, what is the relationship between Cp and Cv?
Cp > Cv
From the following statements regarding the ratio of the molar specific heat at constant pressure to the molar specific heat at constant volume, Cp/Cv, the only correct one for an ideal monatomic gas is
Cp/Cv > 1
From the following statements regarding the ratio of the molar specific heat at constant pressure to the molar specific heat at constant volume, Cp/Cv, the only correct one for an ideal monatomic gas is
Cp/Cv >1
What is the ratio of the pressure that a constant-volume gas thermometer registers at the boiling point of water to the pressure it registers at the freezing point?
D) 1.37
Compared to yesterday, you did 3 times the work in one-third the time. To do so, your power output must have been
D) 9 times yesterday's power output.
Block 1 and block 2 have the same mass, m, and are released from the top of two inclined planes of the same height making 30° and 60° angles with the horizontal direction, respectively. If the coefficient of friction is the same in both cases, which of the blocks is going faster when it reaches the bottom of its respective incline?
D) Block 2 is faster.
A sample of an ideal gas is heated and its Kelvin temperature doubles. What happens to the average speed of the molecules in the sample?
D) It is sqrt(2) times as large.
The pressure drop in a tube carrying a viscous fluid is described by
D) Poiseuille's equation.
A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical frictional force that the pole exerts on the fireman. When this force equals the weight of the fireman, what happens?
D) The fireman continues to descend, but with constant speed.
An object of mass m sits on a flat table. The Earth pulls on this object with force mg, which we will call the action force. What is the reaction force?
D) The object pulling upward on the Earth with force mg.
A car originally at rest has its speed increased to a value v in a period of 5 seconds. The work performed in this part of the motion is W1. Over the next 5 seconds the speed of the car is increased to 2v. In the second part of the motion the work performed is W2. It is correct to say that:
D) W1 = 3W2.
When a solid melts
D) heat energy enters the substance
Convection can occur
D) only in liquids and gases
When you walk barefoot in a room, the floor feels cooler walking on a tile floor as compared to a wooden floor because
D) tile has a larger thermal conductivity than wood.
Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are heated from the same initial temperature, T0, to the same final temperature Tf. You determine that the amount of heat gained by Object 1 is Q. The amount of heat absorbed by Object 2 will be
E) (1/12)Q.
Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are given the same amount of heat. If the temperature of Object 1 changes by an amount ΔT, the change in temperature of Object 2 will be
E) 12ΔT.
Two horizontal pipes are the same length, but pipe B has twice the diameter of pipe A. Water undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe A is Q, what is the flow rate in pipe B?
E) 16Q
A 0.200-kg mass attached to the end of a spring causes it to stretch 5.0 cm. If another 0.200-kg mass is added to the spring, the potential energy of the spring will be
E) 4 times as much.
Work done by STATIC FRICTION is always
E) zero
Radiation
Energy that is radiated or transmitted in the form of rays or waves or particles.
A body moving with constant speed cannot be accelerating.
False
A component of a vector can be greater than the vector's magnitude.
False
A force is required for an object to move.
False
A wave pulse on a string whose end is fixed is reflected without inversion.
False
If work is done on a system by non-conservative forces, the total mechanical energy of a system stays constant.
False
Power is a vector quantity
False
Sound waves in air are transverse waves.
False
T or F: In the first law of thermodynamics, W is the work done on the system, that is W is positive if the work is done on the system
False
T or F: The entropy of a system remains constant during an adiabatic change even if the change is irreversible
False
The acceleration of an object does not have to be in the same direction as the net force applied to it.
False
The buoyant force acting on an object is equal to the weight of the object.
False
The entropy of a system remains constant during an adiabatic change even if the change is irreversible.
False
The force of kinetic friction between two surfaces is dependent on the relative speed of the two surfaces.
False
The frictional force is a conservative force.
False
The preferred positive direction for angular displacement is the clockwise direction.
False
The work required to stretch a spring changes linearly with the amount of stretch.
False
Two objects are thrown vertically upwards simultaneously, one on the surface of Earth and the other on the surface of the Moon. Both have an initial velocity of 20 m/s. Both objects will take the same time to reach the highest point of their trajectory.
False
When a rigid body rotates about a fixed axis all the points in the body have the same angular displacement.
False
When a rigid body rotates about a fixed axis all the points in the body have the same tangential speed.
False
When objects stick together after colliding, the collision is completely elastic.
False
Work is a vector quantity
False
The amount of heat that flows through a rod whose ends are held at different temperatures is proportional to the length of the rod.
False - they're proportional to the area of the rod
2nd law of thermodynamics (heat)
Heat can flow spontaneously from a hot object to a cold object; it will not flow spontaneously from a cold object to a hot object.
When you put an ice cube in a glass of warm tea, which of the following happens? - Neither heat nor cold flows. Only temperature flows between the ice and the tea. - Cold flows from the ice cube into the tea and heat flows from the tea into the ice cube. - Cold flows from the ice cube into the tea. - Heat flows from the tea into the ice cube.
Heat flows from the tea into the ice cube.
Which of the following happens when a material undergoes a phase change? - The chemical composition changes. - The temperature changes. - Heat flows into or out of the material. - The molecules break apart into atoms.
Heat flows into or out of the material.
A dumbbell-shaped object is composed by two equal masses, m, connected by a rod of negligible mass and length r. If I1 is the moment of inertia of this object with respect to an axis passing through the center of the rod and perpendicular to it and I2 is the moment of inertia with respect to an axis passing through one of the masses we can say that
I1<I2
2nd law of thermodynamics (Energy)
In any natural process, some energy becomes unavailable to do useful work
A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample?
It does not change
When atmospheric pressure changes, what happens to the absolute pressure at the bottom of a pool?
It increases by the same amount
Third Law of Thermodynamics
It is impossible to lower the temperature of an object to absolute zero in a finite number of steps
A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper, with the aluminum and the copper in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which object experiences the greater temperature change during the time the system takes to reach thermal equilibrium? - the copper - the aluminum - Neither one; both of them experience the same size temperature change. - It is impossible to tell without knowing the masses. - It is impossible to tell without knowing the volumes.
It is impossible to tell without knowing the masses
Two cars are traveling at the same speed and hit the brakes at the same time. One car has double the deceleration of the other. By what factor does the distance required to stop that car compare with that for the other car?
It takes half the distance to stop
A block of mass M slides down a frictionless plane inclined at an angle(theta) with the horizontal. The normal reaction force exerted by the plane on the block is
Mgcos(theta)
In the absence of an external force, a moving object will
Move with constant velocity
Two men, Joel and Jerry, push against a wall. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do.
Neither of them do any work
A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which object experiences the greater magnitude gain or loss of heat during the time the system takes to reach thermal equilibrium?
Neither; both experience the same size gain or loss of heat
Ideal Gas Law
PV=nRT
One end of a 58-cm-long copper rod with a diameter of 2.8 cm is kept at 480 ∘C, and the other is immersed in water at 22 ∘C. Calculate the heat conduction rate along the rod.
Q/t = 180 J/s
latent heat formula
Q=mL
A wheel of radius R is rolling on a horizontal surface. Its center is moving forward with speed v. A point on the wheel a distance r/3 below the center is moving forward at a speed 2v/3. The wheel is
Rolling without slipping
A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three are released simultaneously at the top of an inclined plane, which will reach the bottom first?
Solid Sphere
The period of a pendulum is the time it takes the pendulum to swing back and forth once. If the only dimensional quantities that the period depends on are the acceleration of gravity, g, and the length of the pendulum, L, what combination of g and L must the period be proportional to? Acceleration has dimensions of [L][T^-2]
Square Root of (L/g)
On the Moon, the acceleration of gravity is g/6. If a pendulum has a period T on Earth, what will its period be on the Moon?
Square Root of 6/T
Two identical samples of a monatomic gas are initially at pressure P and occupy volume V. You perform two experiments which will both lead to the gas samples being compressed to final volumes one-third as large as their initial volumes. In one of the experiments you make the gas undergo an isothermal compression. In the second you make the gas undergo an adiabatic compression. It is correct to say that:
The adiabatic compression leads to a higher final pressure than the isothermal compression and the gas does not exchange heat with its surroundings.
When you blow some air above a paper strip, the paper rises. This is because
The air above the paper moves faster and the pressure is lower
On a cold winter day you turn up the thermostat in your house. Assume that your house is well sealed and that no air enters or leaves the house. When the air temperature in your house rises a short while later, what statement is correct regarding the air pressure?
The air pressure is higher at the higher tempature
heat of vaporization
The amount of energy required for the liquid at its boiling point to become a gas
specific heat
The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius ( Q= mcT)
The rotating systems shown in Figure above differ only in that the two identical movable masses are positioned a distance r from the axis of rotation (left), or a distance r/2 from the axis of rotation (right). If you release the hanging blocks simultaneously from rest,
The block at the right lands first
Conduction
The direct transfer of heat from one substance to another substance that it is touching.
Heat
The energy transferred between objects that are at different temperatures
In a given reversible process, the temperature of an ideal gas is kept constant as the gas is compressed to a smaller volume. What must happen to the gas?
The gas must release heat to its surroundings
In simple harmonic motion, the speed is greatest at that point in the cycle when
The magnitude of the acceleration is minimum
State Kepler's Third Law of Orbital Motion.
The period of a planet's orbit is proportional to the 3/2 power of its average distance from the Sun.
Two equal forces are applied to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force exerts the greater torque?
The second at the doorknob
Sound intensity is defined as
The sound energy passing through a unit of area
Which of the following statements are true as a block of ice melts? Check all that apply. - The temperature of the ice/water system remains constant. - The temperature of the ice/water system increases. - The temperature of the ice/water system decreases. - Heat energy enters the ice/water system. - Heat energy leaves the ice/water system.
The temperature of the ice/water system remains constant. Heat energy enters the ice/water system.
2nd law of thermodynamics (entropy)
The total entropy of an isolated system never decreases
Convection
The transfer of heat by the movement of a fluid
What is meant by "the heat death of the universe"?
The universe will reach thermal equilibrium.
A monatomic ideal gas is compressed isothermically to one-third of its initial volume. The resulting pressure will be
Three times as large as the initial value
When you walk barefoot in a room, the floor feels cooler walking on a tile floor as compared to a wooden floor because
Tile has a larger thermal conductivity than wood.
A net horizontal force is required for a body to move in a horizontal circle.
True
A particle that has zero momentum must also have zero kinetic energy.
True
All reversible engines operating between the same two temperatures have the same efficiency
True
An object floats on a fluid if its density is less than that of the fluid.
True
For uniform circular motion, the velocity and acceleration vectors are perpendicular to each other at every point in the path.
True
Heat is energy that is transferred between objects that are in thermal contact because of a temperature difference.
True
If a thermometer measures the temperature of two objects as being equal, you can conclude that if the objects are placed in thermal contact, no heat will flow between them.
True
In one-dimensional elastic collision of two identical masses, the masses exchange velocities.
True
Internal forces cannot change the total momentum of a system.
True
Non-conservative forces convert mechanical energy into other forms of energy, or convert other forms of energy into mechanical energy.
True
Order in one part of the universe can only be produced at the expense of disorder in another part.
True
T or F: A diesel engine uses adiabatic heating to ignite the fuel
True
T or F: Entropy is a state of function
True
T or F: If a thermometer measures the temperature of two objects as being equal, you can conclude that if the objects are placed in thermal contact, no heat will flow between them
True
T or F: If a thermometer measures the temperature of two objects as being equal, you can conclude that the objects will be in thermal equilibrium if they are brought into thermal contact
True
T or F: In the first law of thermodynamics, Q is the heat gained by the system, that is Q is positive if the system gains heat
True
T or F: Internal energy is a state of function
True
T or F: Neither heat nor work are state of functions
True
T or F: Order in one part of the universe can only be produced at the expense of disorder at another part
True
T or F: The entropy of the surroundings remains constant during an adiabatic change even if the change is irreversible
True
T or F: The entropy of the universe remains constant during reversible adiabatic change
True
T or F: The pressure falls more rapidly in a quasi-static, adiabatic process than along an isotherm when the volume of the gas is increased
True
The banking angle for a properly banked curve does not depend on the mass of the car going over it.
True
The center of mass of a continuous, uniform object is located at the geometric center of the object.
True
The center of mass of an object does not have to be located within the object.
True
The coefficient of static friction is always larger than the coefficient of kinetic friction.
True
The entropy of the surroundings remains constant during an adiabatic change even if the change is irreversible.
True
The force acting on an object is said to be conservative if the work done by this force on the object is independent of the path chosen.
True
The force of kinetic friction between two surfaces is independent of the area of contact between the surfaces.
True
The gravitational force is a conservative force.
True
The horizontal component of the velocity of a projectile remains constant during the entire trajectory of the projectile.
True
The pressure falls more rapidly in a quasi-static, adiabatic process than along an isotherm when the volume of the gas is increased.
True
The sum of kinetic and potential energies of an object is conserved only when the object is under the influence of conservative forces.
True
The vertical component of the acceleration of a projectile remains constant during the entire trajectory of the projectile.
True
When a rigid body rotates about a fixed axis all the points in the body have the same angular acceleration.
True
When comparing two gases at the same temperature, the molecules of the gas with the smaller molecular weight have the higher rms speed.
True
Zeroth Law of Thermodynamics
Two objects placed in thermal contact will eventually come to the same temperature. if two objects are each in equilibrium with a third object, they are also in thermal equilibrium with each other.
First Law of Thermodynamics
U is internal energy of an object, Q is the heat added to it, and W is the work done by the object (delta)U = Q-W
It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it is nighttime. The water is cold! The next day, you go swimming again during the hottest part of the day, and even though the air is warmer the water is still almost as cold. Why? - Water is fairly dense compared with many other liquids. - Water remains in a liquid state for a wide range of temperatures. - Water has a high bulk modulus. - Water has a high specific heat.
Water has a high specific heat
The highest tides occur when
When the Sun and the Moon are on the same side of the Earth.
Work done by static friction is always
Zero
Which of the following are characteristics of a mass in simple harmonic motion?
all of these
Consider a flat steel plate with a hole through its center as shown in Figure above. When that plate's temperature is increased, the hole will
always expand
For periodic motion, the maximum displacement from the equilibrium point is called the
amplitude
The wavelength corresponding to the harmonics of an organ pipe that is open at one end and closed at the other can be found by saying that the length of the pipe must be equal to
an odd number of quarter lengths
Curve A in Figure above represents
an underdamped situation
A mass attached to a vertical spring and bobs up and down between points A and B. Where is the mass located when its kinetic energy is a minimum?
at either A or B
Radiation is emitted - only by objects that have a large specific heat. - only by objects with more caloric than their -surroundings. - by any object not at 0 K. - only by glowing objects such as the Sun. - only by objects whose temperature is greater than the temperature of the surroundings.
by any object not at 0 K.
What is the specific heat of a substance if 130 kJ of heat is needed to raise 6.1 kg of the substance from 18.0 ∘C to 37.2 ∘C?
c = 1100 J/kg⋅C∘
By which primary heat transfer mechanism does one end of a steel rod become hot when the other end is placed in a flame? radiation convection conduction
conduction
A typical thermos bottle has a thin vacuum space between the shiny inner flask (which holds a liquiand the shiny protective outer flask, often stainless steel. The vacuum space is excellent at preventing - conduction, convection, and radiation. - radiation. - convection. - conduction and convection. - conduction.
conduction and convection.
Isobaric Process
constant pressure, Q= U + PV
isothermal process
constant temperature, T=0 makes U=0, so Q=W
isovolumetric process
constant volume (V=0) makes W=0 so Q= U
By which primary heat transfer mechanism does a stove heat a pot of soup? conduction convection radiation
convection
Refer to Figure above. A bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. The coefficient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated, it will
curve downward
The second law of thermodynamics leads us to conclude that - it is theoretically possible to convert heat into work with 100% efficiency. - the total energy of the universe is constant. - disorder in the universe is increasing with the passage of time. - the average temperature of the universe is increasing with the passage of time. - the entropy of the universe remains constant.
disorder in the universe is increasing with the passage of time.
latent heat
energy required to change the phase of a substance
Both beakers A and B in the figure contain a mixture of ice and water at equilibrium. Beaker A has less ice than beaker B. Which beaker is the coldest, or are they equal in temperature? Beaker A. Beaker B. Equal
equal
A monatomic ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be
equal to the initial value
An ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be - equal to the initial value. - nine times the initial value. - more than three times as large as the initial value. - three times as large as the initial value. - impossible to predict on the basis of this data.
equal to the initial value..
A liquid boils when it vapor pressure
equals the external pressure
In Figure above, the block of mass m is at rest on an inclined plane that makes an angle(theta) with the horizontal. The force of static friction f must be such that
f = mgsin(theta)
A boat loaded with rocks is floating in a swimming pool. If the rocks are thrown into the pool, the water level in the pool, after the rocks have settled to the bottom,
falls
When comparing two gases at the same temperature, the gas with a higher molecular weight has more internal energy per mole.
false
An object is released from rest a height h above the ground. A second object with four times the mass of the first is released from the same height. The potential energy of the second object compared to the first is
four times as much
For a periodic process, the number of cycles per unit time is called the
frequency
What is the difference between the pressures inside and outside a tire called?
gauge pressure
An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the most work?
if the pressure increases in proportion to the volume
An ideal monatomic gas undergoes an isothermal expansion. It is correct to affirm that its entropy
increases
A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a clockwise sense around the enclosed area, as shown on the figure, then the change of internal energy over the full cycle is negative. is positive. is zero. cannot be determined from the information given.
is zero
The process shown on the TV graph in the figure is an isothermal compression. adiabatic compression. isobaric compression. isochoric compression.
isothermal compression.
If a system undergoes a reversible process
it must be possible to restore both the system and the surroundings to their original states.
Two metal rods are to be used to conduct heat from a region at 100°C to a region at 0°C as shown in the figure. The rods can be placed in parallel, as shown on the left, or in series, as on the right. When steady state flow is established, the heat conducted in the series arrangement is - greater than the heat conducted with the rods in parallel. - the same as the heat conducted with the rods in parallel. - less than the heat conducted with the rods in parallel.
less than the heat conducted with the rods in parallel.
A sound source departs from a stationary observer. The frequency heard by the observer is
lower than the source
A monatomic ideal gas is compressed adiabatically to one-third of its initial volume. The resulting pressure will be
more than three times as large as the initial value.
Entropy
natural processes tend to move towards a state of greater disorder
Adiabatic process
no heat exchange (Q=0) ΔU = -W
The molar specific heat is the amount of heat required to raise the temperature of what amount of matter by one unit of temperature?
one mole of a substance
The time for one cycle of a periodic process is called the
period
By which primary heat transfer mechanism does the Sun warm Earth? radiation conduction convection
radiation
The process whereby heat flows in the absence of any medium is referred to as
radiation
The fact that a dew drop is spherical is best described in terms of
surface tension
When objects at different temperatures are brought into thermal contact with one another, the resulting spontaneous flow of heat proceeds from the object with the higher
temperature to the one with the lower temperature.
The pitch of a sound is determined by
the frequency
Which has the larger entropy: a gas that occupies only half of a container, with the other half a vacuum, or the same gas occupying the entire container?
the gas occupying the entire container
When a gas expands adiabatically, - it does no work. - the internal (thermal) energy of the gas increases. - the internal (thermal) energy of the gas decreases. -work is done on the gas. - the temperature of the gas remains constant.
the internal (thermal) energy of the gas decreases.
When a gas expands adiabatically,
the internal energy of the gas decreases.
Its more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because
uk < us
A block of mass m slides without friction on a table with speed v. It hits and compresses a spring of force constant k by a distance l. The spring then expands again ejecting the block in the opposite direction as it was originally traveling. Neglecting the mass of the spring, what is the speed of the object after it is ejected by the spring?
v
Second Law of thermodynamics
when objects of different temperatures are brought into thermal contact, the spontaneous flow of heat that results is always from the high temperature object to the low temperature object
Zeroth Law of Thermodynamics
when two objects have the same temperature, they are in thermal equilibrium
On a force vs. position graph, the area under curve is a representation of
work
entropy equation
ΔS=Q/T (in K)
The two forces indicated in Figure above act on a 3.00 kg object. What is the acceleration of the object?
(1.67 m/s^2)X - (0.333 m/s^2)y
The figure shows a pV diagram for 8.3 g of ideal nitrogen gas N2 in a sealed container. The temperature of state 1 is 59°C, the atomic mass of the nitrogen atom is 14 g/mol, and R = 8.31 J/mol • K. What are (a) pressure p1 and (b) temperature T2? (a) 14 atm, (b) 660°C (a) 81 atm, (b) 660°C (a) 14 atm, (b) 120°C (a) 81 atm, (b) 120°C
(a) 81 atm, (b) 660°C
The weather outside is frightful. The temperature is -22 F. What is the corresponding temperature in the Celsius scale?
-30 C
At what temperature are the numerical readings on the Fahrenheit and Celsius scales the same?
-40
The moment of inertia of a uniform rod (about its center) is given by I = ML^2/12. What is the kinetic energy of a 120-cm rod with a mass of 450 g rotating about its center at 3.60 rad/s?
.350 J
The sum of two vectors has the greatest magnitude where angle between these two vectors is
0 degrees
A 320-g mass and a 400-g mass are attached to the two ends of a string that does over a pulley with a radius of 8.70 cm. Because of friction, the pulley does not begin to rotate. What is the magnitude of the frictional torque on the bearing of the pulley if the system is in static equilibrium?
0.00683 Nm
a 320-g air track cart traveling at 1.25 m/s collides elastically with a stationary 270-g cart. What is the speed of the 320-g cart after the collision?
0.106 m/s
The water flowing over Niagara Falls drops a distance of 50 m. If all the gravitational potential energy is converted to thermal energy, by what temperature does the water rise? The specific heat of water is 4186 J/kg • K. 0.12 C° 0.37 C° 0.42 C° 0.10 C°
0.12 C°
Jennifer hits a stationary 200 gram ball and it leaves the racket at 40 m/s. If time lapse photography shows that the ball was in contact with the racket for 40 ms: (a) What average force was exerted on the racket? (b) What is the ratio of this force to the weight of the ball?
0.20 kN, 1.0x10^2
If 150 kcal of heat raises the temperature of 2.0 kg of a material by 400 F°, what is the specific heat capacity of the material? 1.35 kcal/kg • C° 0.34 kcal/kg • C° 0.75 kcal/kg • C° 0.19 kcal/kg • C°
0.34 kcal/kg • C°
How much work is required to stretch a spring 25.2 cm if its force constant is 12.3 N/m?
0.391 J
A 1000-kg helicopter hovers over a forest fire and starts to squirt water downward with a speed of 10 m/s at a rate of 40 kg/s. What is the initial upward acceleration on the helicopter when it first starts to release the water?
0.40 m/s^2
What is the length of a simple pendulum with a period of 2.00s?
0.994 m
Carnot (ideal) efficiency
1-Tl/TH
The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the water pressure at that point? The density of seawater is 1025 kg/m^3
1.11x10^8 Pa
The coefficient of linear expansion of steel is 12 x 10^-6 K^-1. What is the change in length of a 25 m steel bridge span when it undergoes a temperature change of 40 K?
1.2 cm
The coefficient of linear expansion of steel is 12 x 10^-6 K^-1. What is the change in length of a 25-m steel bridge span when it undergoes a temperature change of 40K?
1.2 cm
A mass of 375 g hangs from a string that is wrapped around the circumference of a pulley with a moment of inertia of 0.0125 kgm^2 and a radius of 26.0 cm. When the mass is released, the mass accelerates downward and the pulley rotates about its axis as the string unwinds. What is the tension in the string?
1.21 N
A flatbed truck is carrying a 20.0 kg crate up a sloping road inclined 15.0 degrees above the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?
1.25 m/s^2
In a particle accelerator, a proton reaches an acceleration of 9.0 x 10^13 m/s^2. The mass of a proton is 1.7 x 10^-27 kg. What is the force on the proton?
1.53x10^-13
Figure above represents the velocity of a particle as it travels along the x-axis. What is the average acceleration of the particle between t=1 seconds and t=4 seconds?
1.7 m/s^2
Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are heated from the same initial temperature, T0, to the same final temperature Tf. During this process, if Object 1 absorbs heat Q, the amount of heat absorbed by Object 2 will be 1/12 Q. 4/3 Q. 6Q. 12Q. 3/4 Q.
1/12 Q
An object hits a wall and bounces back with half of its original speed. What is the ratio of the final kinetic energy to the initial kinetic energy?
1/4
Three boxes rest side-by-side on a smooth, horizontal floor. Their masses are 5.0 kg, 3.0 kg, and 2.0 kg, with the 3.0 kg mass in the center. A force of 50 N pushes on the 5.0 kg mass, which pushes against the other two masses. What is the contact force between the 5.0 kg mass and the 3.0 kg mass?
10 N
To determine the height of a flagpole, Abby throws a ball straight up and times it. She sees that the ball goes by the top of the pole after 0.5 s and then reaches the top of the pole again after a total elapsed time of 4.1s. How high is the pole above the point where the ball was launched?
10 m
A harmonic wave has a wavelength of 2.0 m and a frequency of 5.0 Hz. What is the speed of the wave?
10 m/s
Refer to Figure above. If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the distance you have traveled?
10.5 km
Neptune has a radius of 2.48 x 10^7 m and an escape velocity of 23,000 m/s. What is the mass of Neptune? G = 6.67 x 10^-11 Nm^2/kg^2
101 X 10^26 kg
A projectile is shot from the edge of a vertical cliff 60.0m above the ocean. It has a speed of 100 m/s and is fired at an angle of 35.0 degrees above the horizontal. How far from the foot of the vertical cliff does the projectile hit the water?
1080 m
How many cm^2 equal a m^2
10^2
A 20.0 gram mass is attached to a 120 cm long string as shown in Figure above. The tension in the spring is measured to be 0.200 N. What is the angle a?
11.2 Degree
An astronaut stands by the rim of a crater on the moon, where the acceleration for gravity is 1.62 m/s^2 To determine the depth of the crater, she drops a rock and measures the time it takes for it to hit the bottom. If the depth of the crater is 120 m, how long does it take for the rock to fall?
12.2 s
You drop a stone down a well. You hear the splash 1.63 s later. How deep is the well? The speed of sound in air is 343 m/s.
12.5 m
The position of a mass that is oscillating on a spring is given by x=(12.3cm) cos[(1.26 s^-1)t]. What is the speed of the mass when t=0.805s?
13.2 cm/s
A vertical cylindrical cylinder, closed at the bottom end, is fitted at the top with a piston, which can move freely. The mass of the piston is 10.0 kg and the initial height of the piston above the bottom of the cylinder is 25 cm. A mass of 8 kg is placed on the piston, assuming that the temperature is kept constant?
14 cm
A 30.0 kg load is being lifted with constant speed using the ideal pulley arrangement shown in Figure above. What is the magnitude of the force F?
147 N
An object having a fixed emissivity of 0.725 radiates heat at a rate of 10 W when it is at an absolute temperature T. If its temperature is doubled to 2T, at what rate will it now radiate? 80 W 320 W 20 W 160 W 40 W
160W
To what temperature will 7300 J of heat raise 3.5 kg of water that is initially at 18.0 ∘C? The specific heat of water is 4186 J/kg⋅C∘.
18.5 C
A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her moment of inertia decreases by 1/2. Her angular speed increases by a factor of
2
The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively. How long does it take for the football to rise to the highest point of its trajectory?
2.0 s
An airplane is flying at a speed of 200 m/s in level flight at an altitude of 800 m. A package is to be dropped from the airplane to land on a target on the ground. At what horizontal distance away from the target should the package be released so that it lands on the target?
2.55 km
How much heat must be removed from 456 g of water at 25.0 C to change it into ice at -10.0 C? The specific heat of ice is 2090 J/(kg K) and the latent heat of fusion of water is
210 kJ
How much heat must be removed from 456 g of water at 25.0°C to change it into ice at -10.0°C? The specific heat of ice is 2090 J/kg • K, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat of water is 4186 J/kg • K. 47.7 kJ 210 kJ 57.3 kJ 153 kJ 105 kJ
210 kJ
A lab assistant drops a 400.0-g piece of metal at 100.0°C into a 100.0-g aluminum cup containing 500.0 g of water at 15C. In a few minutes, she measures the final temperature of the system to be 40.0°C. What is the specific heat of the 400.0-g piece of metal, assuming that no significant heat is exchanged with the surroundings? The specific heat of this aluminum is 900.0 J/kg • K and that of water is 4186 J/kg • K. 3300 J/kg • K 3800 J/kg • K 1900 J/kg • K 4280 J/kg • K 2270 J/kg • K
2270 J/kg • K
A store sign, with a mass of 20.0 kg and 3.00 m long, has center of gravity at the center of the sign. It is supported by a loose bolt attached to the wall at one end and by a wire at the other end, as shown in figure above The wire makes an angle of 25.0 Degree with the horizontal. What is the tension in the wire?
232 N
How much heat is required to raise the temperature of a 225 g lead ball from 15.0 C to 25.0 C? The specific heat of lead is 128 J/(kgK).
288 J
How much heat is required to raise the temperature of a 225-g lead ball from 15.0 C to 25.0 C? The specific heat of lead is 128 J/(kgK)
288J
A 6.00 m length of rope has a mass of 700 g. It is pulled taught with a force of 100 N. What is the speed of waves on the rope?
29.3 m/s
A gas is taken through the cycle shown in the pV diagram in the figure. During one cycle, how much work is done by the gas? p0V0 4 p0V0 2 p0V0 3 p0V0
3 p0V0
Some properties of a certain glass are listed here: Density 2300 kg/m3 Specific heat capacity 840 J/kg • C° Coefficient of thermal expansion 8.5 × 10-6 (C°)-1 Thermal conductivity 0.80 W/m • C° A glass window pane is 2.7 m high, 2.4 m wide, and 9.0 mm thick. The temperature at the inner surface of the glass is 19C and at the outer surface 4°C. How much heat is lost each hour through the window? 3.1 × 107 J 8.6 × 103 J 3.1 × 105 J 3.1 × 104 J 8.6 J
3.1 × 107 J
A cylinder, semicircular in cross-section, 10.0 m long and 5.00 m in radius, is completely submerged in water. What is the buoyant force on the cylinder?
3.85x10^6
A lab assistant pours 330 g of water at 45°C into an 855-g aluminum container that is at an initial temperature of 10°C. The specific heat of aluminum is 900 J/kg.K and that of water is 4186 J/kg • K. What is the final temperature of the system, assuming no heat is exchanged with the surroundings? 32°C 31°C 33°C 35°C 28°C
32°C
An ideal gas undergoes the process a->b->c->a-> shown in Figure above. Pa = Pc = 360.0 kPa, Vb = vc = 68.00 L, Va = 35.00 L, and Pb = 560.0 kPa. How much work is done by the system in this process?
3300J
A piece of iron of mass 0.12 kg is taken from an oven where its temperature is 336°C and quickly placed in an insulated copper can that contains 0.20 kg of water. The copper can has mass 0.50 kg, and it and the water in it are originally at a temperature of 20°C. Calculate the final temperature of the system, assuming no heat is lost to the surroundings. Use the following specific heats: 4190J/kg • C° (water), 470 J/kg • C° (iron), and 390 J/kg • C° (copper).
36C
A 35-g block of ice at -14 C is dropped into a calorimeter (of negligible heat capacity) containing 400 g of water at 0 C. When the system reaches equilibrium, how much ice is left in the calorimeter? The specific heat of fusion of water is 33.5x10^4 J/kg
38 g
A monatomic ideal gas is compressed isothermally to 1/3 of its initial volume. The resulting pressure will be
3x as large as the initial value
A gas expands from an initial volume of 0.040 m^3 and an initial pressure of 210 kPa to a final volume of 0.065 m^3 while its temperature is kept constant. How much work is done by the system?
4.1 kJ
An object is moving in a circular path with an angular speed of 1.52 rad/s. How long does it take the object to complete one revolution?
4.13 s (divide 6.28[radians in one revolution] by 1.52)
A man is holding an 8.00 kg vacuum cleaner at arm's length, a distance of 0.550 m from his shoulder. What is the torque on the shoulder joint if the arm is horizontal?
43.2 Nm
The melting point of aluminum is 660°C, its latent heat of fusion is 4.00 × 105 J/kg, and its specific heat is 900J/kg • K. How much heat must be added to 500 g of aluminum originally at 27°C to completely melt it? 485 kJ 395 kJ 14 kJ 147 kJ 273 kJ
485 kJ
Vector M = 4.00 m points eastward and vector N = 3.00 m points northward. The resultant vector M+N is given by
5.00 m at an angle 36.9 Degrees north of east
An incompressible fluid flows steadily through a pipe that has a change in diameter. The fluid speed at a location where the pipe diameter is 8.0 cm is 1.28 m/s. What is the fluid speed at a location where the diameter has narrowed to 4.0 cm?
5.12 m/s
An incompressible fluid flows steadily through a pipe that has a change in diameter. The fluid speed at a location where the pipe diameter. The fluid speed at a location where the pipe diameter 8.0 cm is 1.28 m/s. What is the fluid speed at a location where the diameter has a narrowed to 4.0 cm?
5.12 m/s
A simple pendulum of length 2.00 m is made with a mass of 2.00 kg. The mass has a speed of 3.00 m/s when the pendulum is 30.0 degrees above its lowest position. (A) What is the maximum angle away from the lowest position the pendulum will reach? (B) What is the speed of the mass when the pendulum is 45 Degrees above its lowest position?
50.5 Degrees, 1.66 m/s
A solid cylindrical bar conducts heat at a rate of 25 W from a hot to a cold reservoir under steady state conditions. If both the length and the diameter of this bar are doubled, the rate at which it will conduct heat between these reservoirs will be 100 W 200 W 12.5 W 25 W 50 W
50W
A car starts out when the air temperature is 288 K. The air pressure int he tires is 500 kPa. After driving a while, the temperature of the air in the tires increases to 298 K. What is the pressure in the tires at that point assuming the volume remains constant?
517 kPa
A 4.0-kg aluminum block is originally at 10°C. If 160 kJ of heat is added to the block, what is its final temperature? The specific heat capacity of aluminum is 910 J/kg • K. 54°C 34°C 44°C 24°C
54°C
The vertical displacement of a string is given by y(xt) = (6.00 mm)cos[(3.25 m^-1)x-(7.22^1)t] What is the amplitude of the wave?
6.00 mm
Two people are talking at a distance of 3.0 m from where you are and you measure the sound intensity as 1.1 x 10^-7 W/m^2. Another student is 4.0 m away from the talkers. What sound intensity does the other student measure?
6.2 x 10^-8 W/m^2
The peak of Mt. Everest, at 10,900 meters, is the highest point above sea level in the world. What is its elevation in miles?
6.77 miles
A truck is towing a car whose mass is one quarter that of the truck. The force exerted by the truck on the car is 6000 N. The force exerted by the car on the truck is
6000 N
The rms speed of a certain sample of carbon dioxide molecules, with a molecular weight of 44 g/mole is 396 m/s. What is the rms speed of water molecules, with a molecular weight of 18 g/mol at the same temperature?
619 m/s
What is the net power that a person with surface area of 1.20 m2 radiates if his emissivity is 0.895, his skin temperature is 27°C, and he is in a room that is at a temperature of 17°C? (σ = 5.67 × 10-8 W/m2 • K4) 60.3 W 68.4 W 62.6 W 64.8 W 65.7 W
62.6 W
A child is riding a merry-go-round, which has an instantaneous angular speed of 1.25 rad/s and an angular acceleration of 0.745 rad/s^2. The child is standing 4.65 m from the center of the merry-go-round. What angle does the acceleration of the child make the tangential direction?
64.5 Degrees
A 1200 kg car is pulling a 500 kg trailer along level ground. Friction is negligible. The car accelerates with an acceleration of 1.3 m/s^2. What is the force exerted by the car on the trailer?
650 N
A 200-kg superhero, falling from a building manages to grab hold of the end of a 3.0 m long flagpole, 5.0 cm in radius, which saves him from falling any further. After the oscillations have died down, the end of the flagpole is sagging 10 cm. What is the shear modulus of the pole?
7.5x10^6 N/m^2
A 600 kg car is going over a curve with a radius of 120 m that is banked at an angle of 25 degree with a speed of 30.0 m/s . The coefficient of static friction between the car and the road is 0.30. What is the normal force exerted by the road on the car?
7240 N
A glass tea kettle containing 500 g of water is on the stove. The portion of the tea kettle that is in contact with the heating element has an area of 0.090 m2 and is 1.5 mm thick. At a certain moment, the temperature of the water is 75°C, and it is rising at the rate of 3 C° per minute. What is the temperature of the outside surface of the bottom of the tea kettle? Neglect the heat capacity of the kettle, and assume that the inner surface of the kettle is at the same temperature as the water inside. The thermal conductivity of glass is 0.840 W/m • K and the specific heat of water is 4186 J/kg • K. 39°C 92°C 120°C 86°C 77°C
77°C
What is the net power radiated by a little animal with a surface area of 0.075 m2 if his emissivity is 0.75, his skin temperature is 315 K, and he is in a room with a temperature of 290 K? (σ = 5.67 × 10-8 W/m2 • K4) 18 W 8.0 W 8.8 W 6.0 W 15 W
8.8 W
A 40.0kg crate is being raised by means of a rope. Its upward acceleration is 2.00 m/s^2. What is the force exerted by the rope on the crate?
80.0N
A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal energy of the gas?
800 J
An object with a mass of 10.0 kg is at rest at the top of a frictionless inclined plane of height 8.00 m and an angle of inclination 30.0 degrees with the horizontal surface, as shown in Figure 8-9. The coefficient of kinetic friction of kinetic friction for the horizontal surface is 0.400 and g = 10.0 m/s^2. Refer to Figure above. What is the kinetic energy of the object at the bottom of the inclined plane?
800 J
A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal (thermal) energy of the gas? 0 J 800 J 400 J -800 J More information is needed to answer this question.
800J
A heat-conducting rod that is wrapped in insulation is constructed with a 0.15-m length of alloy A and a 0.40-m length of alloy B, joined end-to-end. Both pieces have cross-sectional areas of 0.0020 m2. The thermal conductivity of alloy B is known to be 1.8 times as great as that for alloy A. The end of the rod in alloy A is maintained at a temperature of 10°C, and the other end of the rod is maintained at an unknown temperature. When steady state flow has been established, the temperature at the junction of the alloys is measured to be 40° C, and the rate of heat flow in the rod is measured at 56 W. What is the temperature of the end of the rod in alloy B? 84°C 96°C 88°C 80°C 92°C
84°C
A 10 kg sign is held by two ropes as shown in Figure above. What is the tension on rope A?
88 N
A person drops a brick from the top of a building. The height of the building is 400 m and the mass of the brick is 2.00 kg. What will be the speed of the brick right before it touches the ground? Use g = 10.0 m/s^2
89.4 m/s
How much heat (in joules) is required to raise the temperature of 35.0 kg of water from 20 ∘C to 85 ∘C? The specific heat of water is 4186 J/kg⋅C∘.
9.5×10^6 J
You are on an airplane traveling with a constant velocity at an altitude of 20,000m. What is the acceleration of gravity at that altitude? The radius of Earth is 6.37 x 10^6 m.
9.81 m/s^2
If a vector A has components Ax<0, and Ay<0, then the angle that this vector makes with the positive x-axis must be in the range
90 degrees to 180 degrees
11) The coefficient of linear expansion of steel is 12 × 10-6 K-1. What is the change in length of a 25-m steel bridge span when it undergoes a temperature change of 40 K from winter to summer? A) 1.2 cm B) 1.4 cm C) 1.6 cm D) 1.8 cm E) 2.0 cm
: A
13) A container of 114.0 g of water is heated using of power, with perfect efficiency. How long will it take to raise the temperature of the water from to The specific heat capacity of the container is negligible, and the specific heat capacity of water is 4.186 × 103 J/kg ∙ C. A) 71 s B) 4.1 s C) 17 s D) 320,000 s
: A
14) A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from to The final pressure is What is the change in the internal (thermal) energy of the gas during this process? (R = 8.31 J/mol ∙ K) A) 0.0 kJ B) 3.6 kJ C) 7.2 kJ D) -3.6 kJ E) -7.2 kJ
: A
14) The absolute temperature of a gas is T. In order to double the rms speed of its molecules, what should be the new absolute temperature? A) 4T B) 2T C) T D) 8T E) 16T
: A
15) A hole in a brass plate has a diameter of 1.200 cm at 20°C. What is the diameter of the hole when the plate is heated to 220°C? The coefficient of linear thermal expansion for brass is 19 × 10-6 K-1. A) 1.205 cm B) 1.195 cm C) 1.200 cm D) 1.210 cm
: A
18) The work done on an ideal gas system in an isothermal process is -400 J. What is the change in internal (thermal) energy of the gas? A) 0 J B) -400 J C) 400 J D) 200 J
: A
25) A 2294-kg sample of water at 0° C is cooled to and freezes in the process. How much heat is liberated? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg. The specific heat of ice is 2050 J/kg ∙ K. A) 935,000 kJ B) 597,000 kJ C) 1,110,000 kJ D) 334,000 kJ
: A
3) The figure shows a pV diagram for 2.9 g of ideal oxygen gas O2 in a sealed container. The temperature of state 1 is 76° C, the atomic mass of the oxygen atom is 16 g/mol, and R = 8.31 J/mol ∙ K. What are the temperatures T3 and T4? A) -11° C and 510° C B) 57° C and 170° C C) 260° C and 790° C D) 38° C and 110° C
: A
33) A certain heat engine extracts 1.30 kJ of heat from a hot temperature reservoir and discharges 0.70 kJ of heat to a cold temperature reservoir. What is the efficiency of this engine? A) 46% B) 54% C) 86% D) 27% E) 13%
: A
33) A glass flask has a volume of 500 mL at a temperature of 20° C. The flask contains 492 mL of mercury at an equilibrium temperature of 20°C. The temperature is raised until the mercury reaches the 500 mL reference mark. At what temperature does this occur? The coefficients of volume expansion of mercury and glass are 18 ×10-5 K-1 (mercury) and 2.0 ×10-5 K-1 (glass). A) 120°C B) 110°C C) 100°C D) 140°C E) 130°C
: A
33) Heat is added to a 3.0 kg piece of ice at a rate of How long will it take for the ice at 0.0° C to melt? For water LF = 334,000 J/kg and LV = 2.246 × 106 J/kg. A) 1.6 s B) 640,000 s C) 0.0 s D) 1000 s
: A
37) A 771.0-kg copper bar is put into a smelter for melting. The initial temperature of the copper is 300.0 K. How much heat must the smelter produce to completely melt the copper bar? The specific heat for copper is 386 J/kg∙K, the heat of fusion for copper is 205,000 J/kg, and its melting point is 1357 K. A) 4.73 × 105 kJ B) 3.15 × 1011 kJ C) 3.15 × 108 kJ D) 5.62 × 105 kJ
: A
43) A gas follows the pV trajectory shown in Figure 16.2. How much work is done per cycle by the gas if The gas in a heat engine follows the cycle shown in the pV diagram. How much work does this engine do each cycle if p0 = A) 220 J B) 440 J C) 870 J D) 1100 J
: A
47) An ideal Carnot heat engine has an efficiency of 0.600. If it operates between a deep lake with a constant temperature of and a hot reservoir, what is the temperature of the hot reservoir? A) 735 K B) 490 K C) 470 K D) 784 K
: A
5) The figure shows a pV diagram for 0.0061 mol of ideal gas that undergoes the process 1 → 2 → 3. What is the pressure p2? (R = 8.31 J/mol ∙ K) A) 4.9 atm B) 4.9 × 105 atm C) 15 atm D) 1.5 × 106 atm
: A
59) A sealed cylinder fitted with a movable piston contains ideal gas at 27°C, pressure 0.500 × 105 Pa, and volume 1.25 m3. What will be the final temperature if the gas is compressed to 0.800 m3 and the pressure rises to 0.820 × 105 Pa? A) 42°C B) 68°C C) 130°C D) 250°C E) 150°C
: A
68) What is the average translational kinetic energy of a nitrogen molecule in the air in a room in which the air temperature is 17°C? The Boltzmann constant is 1.38 × 10-23 J/K. A) 6.01 × 10-21 J B) 4.00 × 10-21 J C) 5.00 × 10-21 J D) 7.00 × 10-21 J E) 9.00 × 10-21 J
: A
70) A solid concrete wall has dimensions 4.0 m × 2.4 m and is 30 cm thick. The thermal conductivity of the concrete is 1.3 W/m ∙ K, and it separates a basement from the ground outside. The inner surface of the wall is at 18°C, and the outside surface is at 6°C. How much heat flows through the wall every hour? A) 1.8 MJ B) 1.8 kJ C) 500 J D) 5.0 MJ E) 5.0 kJ
: A
72) At what temperature would the root mean square speed of oxygen molecules, O2, be if oxygen behaves like an ideal gas? The mass of one O2 molecule is 5.312 × 10-26 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. A) 0.251 K B) 2090 K C) 6270 K D) 1.52 × 1023 K
: A
75) An ideal reversible heat pump is taking heat from the outside air at -10.0°C and discharging it into the house at 18.0°C. What is the coefficient of performance of this heat pump? A) 10.4 B) 9.44 C) 0.644 D) 0.533 E) 0.0962
: A
79) An ideal Carnot engine is operated as an air conditioner to cool a house in the summer. The air conditioner removes of heat per second from the house, and maintains the inside temperature at while the outside temperature is The power required to run the air conditioner under these operating conditions is closest to A) 3600 W. B) 4400 W. C) 5100 W. D) 5800 W. E) 6600 W.
: A
8) A compression at a constant pressure of 200 kPa is performed on 8.00 moles of an ideal monatomic gas. The compression reduces the volume of the gas from to How much work was done by the gas during this process? A) -16 kJ B) 16 kJ C) -40 kJ D) 40 kJ E) 0 kJ
: A
87) An irreversible engine operating between the temperatures of 550 K and 300 K extracts 1.20 kJ of heat from the hot reservoir and produces 0.450 kJ of work. How much entropy is created in the process? A) 0.32 J/K B) 0.68 J/K C) 0.44 J/K D) 0.73 J/K E) 0 J/K
: A
9) A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. Half of the kinetic energy of the hammer is transformed into heat in the nail and does not flow out of the nail. What is the increase in temperature of the nail after the three blows that the carpenter needs to drive the nail in completely? The specific heat of steel is 448 J/kg ∙ K. A) 8.1 K B) 3.6 K C) 1.8 K D) 2.7 K E) 7.7 K
: A
1) Express a body temperature 98.6°F in Celsius degrees. A) 37.0°C B) 45.5°C C) 66.6°C D) 72.6°C
: A
1) The figure shows a pV diagram for 2.6 g of ideal helium gas that undergoes the process 1 → 2 → 3. Find the value of volume V3. The atomic mass of helium is 4.0 g/mol, and R = 8.31 J/mol ∙ K. A) 25 L B) 99 L C) 50 L D) 12 L
: A
1) When a gas expands adiabatically, A) the internal (thermal) energy of the gas decreases. B) the internal (thermal) energy of the gas increases. C) it does no work. D) work is done on the gas. E) the temperature of the gas remains constant.
: A
10) Platinum melts at 3215°F. What is the corresponding temperature in the Kelvin scale? A) 2041 K B) 2135 K C) 2207 K D) 2296 K E) 3215 K
: A
10) The figure shows a pV diagram for an ideal gas that is carried around a cyclic process. How much work is done in one cycle if p0 = and L? (1.00 atm = 101 kPa) A) 1210 J B) 485 J C) 2280 J D) 2420 J E) 4850 J
: A
11) A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal (thermal) energy of the gas? A) 800 J B) -800 J C) 400 J D) 0 J E) More information is needed to answer this question.
: A
11) It is necessary to determine the specific heat of an unknown object. The mass of the object is It is determined experimentally that it takes to raise the temperature What is the specific heat of the object? A) 7.46 J/kg ∙ K B) 1500 J/kg ∙ K C) 0.00130 J/kg ∙ K D) 3,020,000 J/kg ∙ K
: A
12) A 920-g empty iron kettle is put on a stove. How much heat in joules must it absorb to raise its temperature form to The specific heat for iron is 113 cal/kg ∙ C°, and 1 cal = 4.186 J. A) 33,900 J B) 40,500 J C) 8110 J D) 40,100 J
: A
12) A gas expands from an initial volume of 30.0 L to a final volume of 65.0 L at a constant pressure of 110 kPa. How much work is done by the gas during this expansion? A) 3.85 kJ B) 10.4 kJ C) 3850 kJ D) 10.4 MJ E) 3.85 MJ
: A
12) If, with steady state heat flow established, you double the thickness of a wall built from solid uniform material, the rate of heat loss for a given temperature difference across the thickness will A) become one-half its original value. B) also double. C) become one-fourth its original value. D) become 1/ of its original value. E) become four times its original value.
: A
13) An aluminum rod 17.400 cm long at 20°C is heated to 100°C. What is its new length? Aluminum has a linear expansion coefficient of 25 × 10-6 K-1. A) 17.435 cm B) 17.365 cm C) 0.348 cm D) 0.0348 cm
: A
14) A 6.5-g iron meteor hits the earth at a speed of 295 m/s. If its kinetic energy is entirely converted to heat in the meteor, by how much will its temperature rise? The specific heat of iron is 113 cal/kg ∙ C°, and 1 cal = 4.186 J. A) 92.0 C° B) 57,100 C° C) 0.147 C° D) 384 C°
: A
15) A glass beaker of unknown mass contains of water. The system absorbs of heat and the temperature rises as a result. What is the mass of the beaker? The specific heat of glass is 0.18 cal/g ∙ °C, and that of water is 1.0 cal/g ∙ C°. A) 140 g B) 560 g C) 540 g D) 270,000 g
: A
16) During an isothermal process, 5.0 J of heat is removed from an ideal gas. What is the change in internal (thermal) energy of the gas? A) 0 J B) 2.5 J C) 5.0 J D) 10 J
: A
16) On his honeymoon, James Joule attempted to explore the relationships between various forms of energy by measuring the rise of temperature of water which had fallen down a waterfall on Mount Blanc. What maximum temperature rise would one expect for a waterfall with a vertical drop of 20 m? The specific heat of water is 4186 J/kg ∙ K. A) 0.047 C° B) 0.053 C° C) 0.064 C° D) 0.071 C°
: A
17) If the efficiency of a Carnot engine were to be 100%, the heat sink would have to be A) at absolute zero. B) at 0°C. C) at 100°C. D) infinitely hot.
: A
18) In a flask, 114.0 g of water is heated using of power, with perfect efficiency. How long will it take to raise the temperature of the water from to The specific heat of water is 4186 J/kg ∙ K. A) 71 s B) 4.1 s C) 17 s D) 320,000 s
: A
2) An ideal gas is compressed isothermally to one-third of its initial volume. The resulting pressure will be A) three times as large as the initial value. B) less than three times as large as the initial value. C) more than three times as large as the initial value. D) equal to the initial value. E) impossible to predict on the basis of this data.
: A
2) The figure shows a pV diagram for 8.3 g of ideal nitrogen gas N2 in a sealed container. The temperature of state 1 is 59°C, the atomic mass of the nitrogen atom is 14 g/mol, and R = 8.31 J/mol ∙ K. What are (a) pressure p1 and (b) temperature T2? A) (a) 81 atm, (b) 660°C B) (a) 14 atm, (b) 660°C C) (a) 81 atm, (b) 120°C D) (a) 14 atm, (b) 120°C
: A
21) In an isochoric process, the internal (thermal) energy of a gas decreases by 50 J. How much work is done by the gas during this process? A) 0 J B) 50 J C) -50 J D) 25 J E) -25 J
: A
23) A fixed amount of an ideal monatomic gas is maintained at constant volume as it is cooled by 50 K. This feat is accomplished by removing 400 J of energy from the gas. How much work is done by the gas during this process? A) 0 J B) 400 J C) -400 J D) -200 J E) 200 J
: A
23) If you add 700 kJ of heat to 700 g of water originally at 70.0°C, how much water is left in the container? The latent heat of vaporization of water is 22.6 × J/kg, and its specific heat capacity is 4186 J/kg ∙ K. A) 429 g B) 258 g C) 340 g D) 600 g E) none
: A
24) The coefficient of linear expansion of aluminum is 24 × 10-6 K-1 and the coefficient of volume expansion of olive oil is 0.68 × 10-3 K-1. A novice cook, in preparation of some pesto, fills a 1.00-L aluminum pot to the brim and heats the oil and the pot from an initial temperature of 15°C to 190°C. To his consternation some olive oil spills over the top. How much? A) 0.11 L B) 0.12 L C) 0.13 L D) 0.14 L E) 0.15 L
: A
25) The gas in a perfectly insulated but flexible container does work at a rate of At what rate is the internal (thermal) energy of the gas changing? A) -13 W B) 13 W C) 0 W D) 6.5 W
: A
26) A fluid in an insulated, flexible bottle is heated by a high resistance wire and expands. If of heat is applied to the system and it does of work, how much does the internal (thermal) energy of the fluid change? A) 4.0 kJ B) 14 kJ C) -4.0 kJ D) 45 kJ
: A
26) The melting point of aluminum is 660°C, its latent heat of fusion is 4.00 × 105 J/kg, and its specific heat is 900J/kg ∙ K. How much heat must be added to 500 g of aluminum originally at 27°C to completely melt it? A) 485 kJ B) 395 kJ C) 273 kJ D) 147 kJ E) 14 kJ
: A
29) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. The heat gained by the gas in process a→b is 546 J, while in process the gas loses 62.0 J of heat. In process a→b the gas performs of work, while in process c→a 223 J of work is done on the gas. How much heat is gained by the gas in process c→a? A) -397 J B) -62 J C) 223 J D) 18 J E) -236 J
: A
3) A person consumes a snack containing 14 food calories (14 kcal). What is the power this food produces if it is to be "burned off" due to exercise in 6 hours? (1 cal = 4.186 J) A) 2.7 W B) 9763 W C) 0.6 W D) 0.0027 W
: A
30) A steel pipe 36.0 m long, installed when the temperature was is used to transport superheated steam at a temperature of Steel's coefficient of linear expansion is . The pipe is allowed to expand freely when the steam is transported. What is the increase in the length of the pipe when it is used with the superheated steam? A) 60 mm B) 57 mm C) 54 mm D) 64 mm E) 67 mm
: A
31) An aluminum rod is 10.0 cm long and a steel rod is 80.0 cm long when both rods are at a temperature of 15°C. Both rods have the same diameter. The rods are now joined end-to-end to form a rod 90.0 cm long. If the temperature is now raised from 15°C to 90°C, what is the increase in the length of the joined rod? The coefficient of linear expansion of aluminum is 2.4 × 10-5 K-1 and that of steel is 1.2 × 10-5 K-1. A) 0.90 mm B) 0.81 mm C) 0.72 mm D) 0.63 mm E) 0.99 mm
: A
32) A 45.0-kg sample of ice is at 0.00° C. How much heat is needed to melt it? For water LF = 334,000 J/kg and LV = 2.256 × 106 J/kg. A) 1.50 × 104 kJ B) 4.10 × 106 kJ C) 0.00 kJ D) 1.02 × 105 kJ
: A
32) A brass rod is 69.5 cm long and an aluminum rod is 49.3 cm long when both rods are at an initial temperature of 0° C. The rods are placed in line with a gap of 1.2 cm between them, as shown in the figure. The distance between the far ends of the rods is maintained at 120.0 cm throughout. The temperature of both rods is raised equally until they are barely in contact. At what temperature does contact occur? The coefficients of linear expansion of brass and aluminum are 2.0 ×10-5 K-1 (brass) and 2.4 × 10-5 K-1 (aluminum). A) 470°C B) 440°C C) 420°C D) 490°C E) 510°C
: A
32) A heat engine receives 7000 J of heat and loses 3000 J in each cycle. What is the efficiency of this engine? A) 57% B) 30% C) 70% D) 43%
: A
34) A .20-kg ice cube at 0.0°C has sufficient heat added to it to cause total melting, and the resulting water is heated to How much heat is added? For water LF = 334,000 J/kg, LV = 2.256 × 106 J/kg, the c = 4.186 x 103 J/kg ∙ C. A) 130 kJ B) 14,000 kJ C) 81 kJ D) 59 kJ
: A
34) A heat engine with an efficiency of 30% performs 2500 J of work. How much heat is discharged to the lower temperature reservoir? A) 5800 J B) 8300 J C) 750 J D) 1400 J E) 7100 J
: A
35) How much heat must be added to a 8.0-kg block of ice at -8°C to change it to water at The specific heat of ice is 2050 J/kg ∙ C°, the specific heat of water is 4186 J/kg ∙ C°, the latent heat of fusion of ice is 334,000 J/kg, and 1 cal = 4.186 J. A) 780 kcal B) 140 kcal C) 180 kcal D) 810 kcal E) 730 kcal
: A
36) When a sample of water at 0.0°C is cooled to -36.0°C and freezes in the process, 935,000 kJ of heat is liberated. What is the mass of this sample of water? For water LF = 334,000 J/kg, LV = 2.256 × 106 J/kg, and the specific heat of ice is 2050 J/kg ∙ C°. A) 2290 kg B) 1145 kg C) 2800 kg D) 12,700 kg
: A
38) A substance has a melting point of 20°C and a heat of fusion of 3.4 × J/kg. The boiling point is and the heat of vaporization is at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ∙ K (solid), 1000 J/kg ∙ K (liquid), and 400 J/kg ∙ K (gaseous). How much heat is required to raise the temperature of of this substance from to at a pressure of one atmosphere? A) 260 kJ B) 190 kJ C) 230 kJ D) 92 kJ E) 320 kJ
: A
39) A substance has a melting point of 20°C and a heat of fusion of The boiling point is and the heat of vaporization is at a pressure of one atmosphere. The specific heats for the solid, liquid, and gaseous phases are 600 J/kg ∙ K (solid), 1000 J/kg ∙ K (liquid), and 400 J/kg ∙ K (gaseous). How much heat is given up by of this substance when it is cooled from 170°C to 86°C at a pressure of one atmosphere? A) 400 kJ B) 200 kJ C) 300 kJ D) 440 kJ E) 640 kJ
: A
4) The figure shows a pV diagram for 0.98 mol of ideal gas that undergoes the process 1 → 2. The gas then undergoes an isochoric heating from point 2 until the pressure is restored to the value it had at point 1. What is the final temperature of the gas? (R = 8.31 J/mol ∙ K). A) -160°C B) 12°C C) 380°C D) 110°C
: A
40) A person tries to heat up her bath water by adding 5.0 L of water at 80°C to 60 L of water at 30°C. What is the final temperature of the bath water? A) 34°C B) 36°C C) 38°C D) 40°C
: A
41) A nuclear power plant has an actual efficiency of 33%. If of energy are released from fission, how much electric power does the power plant produce? A) 0.063 MW B) 6.3 MW C) 25 MW D) 0.25 MW
: A
42) The figure shows a pV diagram for a cycle of a heat engine for which QH = 59 J. What is the thermal efficiency of the engine? A) 17% B) 34% C) 8.5% D) 14%
: A
43) A 90-g aluminum calorimeter contains 390 g of water at an equilibrium temperature of A piece of metal, initially at is added to the calorimeter. The final temperature at equilibrium is 32° C. Assume there is no external heat exchange. The specific heat capacities of aluminum and water are 910 J/kg ∙ K (aluminum) and 4190 J/kg ∙ K (water). What is the specific heat capacity of the 160-g piece of metal? A) 470 J/kg ∙ K B) 430 J/kg ∙ K C) 350 J/kg ∙ K D) 310 J/kg ∙ K E) 510 J/kg ∙ K
: A
45) A lab student drops a 400.0-g piece of metal at 120.0°C into a cup containing 450.0 g of water at 15.0°C. After waiting for a few minutes, the student measures that the final temperature of the system is 40.0°C. What is the specific heat of the metal, assuming that no significant heat is exchanged with the surroundings or the cup? The specific heat of water is 4186 J/kg ∙ K. A) 1470 J/kg ∙ K B) 2830 J/kg ∙ K C) 3420 J/kg ∙ K D) 3780 J/kg ∙ K E) 4280 J/kg ∙ K
: A
46) An ideal Carnot heat engine operates between and What is its efficiency? A) 0.38 B) 0.62 C) 0.61 D) 1.61
: A
47) A jogger is running outdoors on a cold day when the temperature is -20.0°C. She is breathing at the rate of 25 breaths per minute, and each time she breathes in she inhales 0.00450 m3 of air. How much heat does she lose from breathing during 20.0 minutes of jogging if the air in her lungs is heated to her body temperature of 37.0°C before it is exhaled? The specific heat of air is 1020 J/kg ∙ K and the density of air under typical conditions is 1.29 kg/m3. A) 169 kJ B) 278 kJ C) 354 kJ D) 431 kJ E) 543 kJ
: A
48) An ideal Carnot engine extracts 529 J of heat from a high-temperature reservoir during each cycle, and rejects of heat to a low-temperature reservoir during the same cycle. What is the efficiency of the engine? A) 0.57 B) 1.35 C) 2.35 D) 0.7
: A
49) A laboratory vacuum pump can reduce the pressure in a chamber to 1.0 × 10-7 Pa. If the volume of the chamber is 0.500 m3 and the temperature is 27°C, how many molecules are left inside the chamber? (NA = 6.022 × 1023 molecules/mol, R = 8.31 J/mol ∙ K) A) 1.2 × 1013 B) 2.4 × 1013 C) 1.2 × 1012 D) 2.4 × 1012 E) 1.2 × 1014
: A
50) A 0.600-kg piece of metal X is heated to 100°C and placed in an aluminum can of mass 0.200-kg which contains 0.500 kg of water initially at 17.3°C. The final equilibrium temperature of the mixture is 20.2°C, what is the specific heat of metal X? The specific heats of water and aluminum are 4186 J/kg ∙ K (water) and 910 J/kg ∙ K (aluminum). A) 140 J/kg ∙ K B) 270 J/kg ∙ K C) 450 J/kg ∙ K D) 900 J/kg ∙ K
: A
50) A refrigerator has an interior volume of 0.500 m3. The temperature inside the refrigerator in 282 K, and the pressure is 101 kPa. If the molecular weight of air is 29 g/mol, what is the mass of air inside the refrigerator? (R = 8.31 J/mol × K) A) 625 g B) 513 g C) 447 g D) 329 g E) 243 g
: A
53) An ideal Carnot engine has an efficiency of 83.0% and performs 4500 J of work every cycle. How much energy is discharged to the lower temperature reservoir every cycle? A) 920 J B) 830 J C) 740 J D) 3700 J E) 5400 J
: A
54) A 5.3 L flask of ideal neon gas (which is monatomic) is at a pressure of 6.0 atm and a temperature of The atomic mass of neon is 20.2 g/mol. What is the mass of the neon gas in the flask. (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa, NA = 6.022 × 1023 molecules/mol) A) 2.7 × 10-2 B) 1.6 × 10-2 C) 1.3 × 101 D) 2.7 × 101 E) 2.7 × 103
: A
55) A 4.2-L flask of ideal neon gas (which is monatomic) is at a pressure of 3.3 atm and a temperature of 450 K. The atomic mass of neon is 20.2 g/mol. How many neon atoms are in the flask? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa, NA = 6.022 × 1023 molecules/mol) A) 2.3 × 1023 B) 2.3 × 1022 C) 6.9 × 1023 D) 2.3 × 1025 E) 6.9 × 1022
: A
55) A 44.0-g block of ice at -15.0°C is dropped into a calorimeter (of negligible heat capacity) containing of water at 5.0°C. When equilibrium is reached, how much of the ice will have melted? The specific heat of ice is 2090 J/kg ∙ K, that of water is 4186 J/kg ∙ K, and the latent heat of fusion of water is 33.5 × 104 J/kg. A) 2.1 g B) 21 g C) 5.2 g D) 52 g E) 4.4 g
: A
56) A 3.9-L volume of ideal neon gas (monatomic) is at a pressure of 5.6 aym and a temperature of The atomic mass of neon is The temperature of the gas is now increased to 430 K and the volume is increased to What is the final pressure of the gas? A) 4.8 atm B) 4.3 atm C) 5.3 atm D) 5.8 atm E) 6.3 atm
: A
57) A 0.40- gas tank holds 7.0 moles of ideal diatomic nitrogen gas at a temperature of The atomic mass of nitrogen is . What is the pressure of the gas? (R = 8.31 J/mol ∙ K, 1 atm = 101 kPa) A) 42 atm B) 37 atm C) 32 atm D) 27 atm E) 22 atm
: A
57) A 400-g block of iron at 400°C is dropped into a calorimeter (of negligible heat capacity) containing 60 g of water at 30°C. How much steam is produced? The latent heat of vaporization of water is 22.6 × 105 J/kg and its specific heat capacity is 4186 J/kg ∙ K. The average specific heat of iron over this temperature range is 560 J/kg ∙ K. A) 22 g B) 33 g C) 42 g D) 54 g E) 59 g
: A
57) An ideal Carnot engine operates between a high temperature reservoir at and a river with water at If it absorbs of heat each cycle, how much work per cycle does it perform? A) 1642 J B) 2358 J C) 1483 J D) 2517 J
: A
59) A 360-g metal container, insulated on the outside, holds 180.0 g of water in thermal equilibrium at 22.0°C. A 24.0-g ice cube, at the melting point, is dropped into the water, and when thermal equilibrium is reached the temperature is 15.0°C. Assume there is no heat exchange with the surroundings. For water, the specific heat capacity is 4190 J/kg ∙ K and the heat of fusion is 3.34 × 105 J/kg. What is the specific heat capacity of the metal of the container? A) 1700 J/kg ∙ K B) 970 J/kg ∙ K C) 2300 J/kg ∙ K D) 2800 J/kg ∙ K E) 3300 J/kg ∙ K
: A
59) An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at has an efficiency of What is the temperature of the warm reservoir? A) 2.93 K B) 0.0500 K C) 106 K D) 0.0400 K
: A
6) The figure shows a pV diagram for 0.0077 mol of ideal gas that undergoes the process 1 → 2 → 3. What is the volume V3? (R = 8.31 J/mol ∙ K) the volume V3? A) 770 B) 0 C) 0 D) 400
: A
60) An ideal Carnot engine operates between a warm reservoir at 233 K and a colder reservoir. During each cycle, this engine extracts of heat from the warm reservoir and does of work. What is the temperature of the colder reservoir? A) 171 K B) 62 K C) 47 K D) 67 K
: A
61) What is the efficiency of an ideal Carnot engine operating between a reservoir in which ice and water coexist, and a reservoir in which water and steam coexist? The pressure is constant at 1.0 atm for both reservoirs. A) 27% B) 0.27% C) 100% D) 1.0% E) 15%
: A
62) An ideal Carnot engine operating between a warm reservoir of unknown temperature and a cold reservoir at has an efficiency of What is the temperature of the warm reservoir? A) 1.98 K B) 0.180 K C) 157 K D) 0.160 K
: A
63) A heat-conducting rod, 0.90 m long and wrapped in insulation, is made of an aluminum section that is 0.20 m long and a copper section that is long. Both sections have a cross-sectional area of The aluminum end and the copper end are maintained at temperatures of and respectively. The thermal conductivities of aluminum and copper are 205 W/m ∙ K (aluminum) and 385 W/m ∙ K (copper). What is the temperature of the aluminum-copper junction in the rod with steady state heat flow? A) 100°C B) 93°C C) 86°C D) 80°C E) 74°C
: A
64) A heat conducting rod, 1.60 m long and wrapped in insulation, is made of an aluminum section that is 0.90 m long and a copper section that is long. Both sections have a cross-sectional area of The aluminum end and the copper end are maintained at temperatures of and respectively. The thermal conductivities of aluminum and copper are 205 W/m ∙ K (aluminum) and 385 W/m ∙ K (copper). At what rate is heat conducted in the rod under steady state conditions? A) 9.0 W B) 7.9 W C) 10 W D) 11 W E) 12 W
: A
65) A Carnot engine operates between two reservoirs with unknown temperatures. If the Carnot engine operates at efficiency, what is the ratio of the absolute temperatures of the reservoirs, Tc/Th? A) 0.33 B) 0.0012 C) 0.0025 D) 0.67
: A
65) What is the average translational kinetic energy of an ideal gas at The Boltzmann constant is 1.38 × 10-23 J/K. A) 1.70 x 10-20 J B) 5.65 x 10-21 J C) 1.13 x 10-17 J D) 3.77 x 10-19 J
: A
67) A glass window pane is 2.7 m high, 2.4 m wide, and 9.0 mm thick. The temperature at the inner surface of the glass is and at the outer surface 4°C. How much heat is lost each hour through the window? A) 3.1 × 107 J B) 3.1 × 104 J C) 8.6 × 103 J D) 8.6 J E) 3.1 × 105 J
: A
7) The temperature of an ideal gas in a sealed rigid 0.20- container is reduced from 360 K to and the final pressure of the gas is How much work is done by the gas during this process? (R = 8.31 J/mol ∙ K) A) 0 kJ B) -9.0 kJ C) -12 kJ D) 9.0 kJ E) 12 kJ
: A
71) A 0.50 gas tank holds 3.0 moles of ideal diatomic nitrogen gas at a temperature of The atomic mass of nitrogen is . What is the rms speed of the molecules? (The Boltzmann constant is 1.38 × 10-23 J/K, NA = 6.022 × 1023 molecules/mol.) A) 560 B) 790 C) 390 D) 21 E) 97
: A
73) If the temperature of a gas is increased from 20°C to 100°C, by what factor does the rms speed of an ideal molecule change? A) 1.1 B) 1.3 C) 2.2 D) 1.6
: A
74) Two metal rods, one silver and the other gold, are attached to each other end-to-end. The free end of the silver rod is immersed in a steam chamber at 100°C, and the free end of the gold rod in an ice water bath at 0°C. The rods are both 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and their surroundings, except at the ends. How much total heat flows through the two rods each minute? The thermal conductivity of silver is 417 W/m ∙ K, and that of gold is 291 W/m ∙ K. A) 8.2 kJ B) 9.5 kJ C) 12 kJ D) 14 kJ E) 16 kJ
: A
75) Dust particles in a grain elevator frequently have masses of the order of 1.0 × 10-9 kg. If, to a first approximation, we model the dust particles as an ideal gas, what would be the rms speed of such a particle in air at 27°C? The Boltzmann constant is 1.38 × 10-23 J/K . A) 3.5 × 10-6 m/s B) 5.6 × 10-5 m/s C) 7.8 × 10-4 m/s D) 5.2 × 10-3 m/s E) 4.9 × 10-2 m/s
: A
77) If the temperature of an ideal gas is increased from 20°C to 40°C, by what percent does the speed of the molecules increase? A) 3% B) 30% C) 70% D) 100%
: A
78) A Carnot air conditioner has a coefficient of performance of 17.0 and removes 72.0 MJ of heat from the interior of a house every hour. How much power does it consume? A) 1180 W B) 1320 W C) 520 kW D) 3.14 MW E) 1.25 MW
: A
80) An ideal Carnot engine is operated as a heat pump to heat a room in the winter. The heat pump delivers heat to the room at the rate of 47 kJ per second and maintains the room at a temperature of 293 K when the outside temperature is 237 K. The power requirement to run the heat pump under these operating conditions is closest to A) 9000 W. B) 7100 W. C) 20,000 W. D) 15,000 W. E) 11,000 W.
: A
81) An ideal Carnot refrigerator with a performance coefficient (COP) of 5.0 cools items inside of it to What is the high temperature needed to operate this refrigerator? A) 61° C B) 1395° C C) 6° C D) 30° C
: A
82) A heat pump with a performance coefficient (COP) of 4.9 absorbs heat from the atmosphere at a rate of At what rate is work being done to run this heat pump? A) 6 kW B) 142 kW C) 113 kW D) 35 kW
: A
85) What is the change in entropy when 15.0 g of water at 100°C are turned into steam at 100°C? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) 90.8 J/K B) -90.8 J/K C) 339 J/K D) -339 J/K E) 0 J/K
: A
86) What is the net power radiated by a little animal with a surface area of 0.075 m2 if his emissivity is 0.75, his skin temperature is 315 K, and he is in a room with a temperature of 290 K? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 8.8 W B) 6.0 W C) 8.0 W D) 15 W E) 18 W
: A
87) The radius of a star is 6.95 × 108 m, and its rate of radiation has been measured to be 5.32 × 1026 W. Assuming that it is a perfect emitter, what is the temperature of the surface of this star? (σ = 5.67 × 10-8 W/m2 ∙ K4) A) 6.27 × 103 K B) 8.25 × 103 K C) 8.87 × 103 K D) 3.93 × 107 K E) 5.78 × 107 K
: A
88) On a cold winter day, the outside temperature is -20°C and the inside temperature is maintained at 20°C. There is a net heat flow to the outside through the walls, roof, etc., of 25 kW. What is the rate of increase of the entropy of the universe as a result of this heat flow? A) 13 W/K B) 25 W/K C) 85 W/K D) 99 W/K E) 0 W/K
: A
9) An expansion process on an ideal diatomic ideal gas has a linear path between the initial and final coordinates on a pV diagram. The coordinates of the initial state are: the pressure is 300 kPa, the volume is and the temperature is The final pressure is and the final temperature is How much work is done by the gas during this process? (R = 8.31 J/mol ∙ K) A) 13,000 J B) 6300 J C) 9400 J D) 16,000 J E) 19,000 J
: A
90) A 0.42-kg quantity of ethanol, in the liquid state at its melting point of -114.4°C, is frozen at atmospheric pressure. The heat of fusion of ethanol is 1.04 × 105 J/kg, and its molecular mass is 46.1 g/mol. What is the change in the entropy of the ethanol as it freezes? A) -280 J/K B) -250 J/K C) -310 J/K D) 250 J/K E) 280 J/K
: A
10) A 10-L flask and a 1-L flask each contain two moles of ideal diatomic gas (but not the same gas) at 25°C. Which of the following statements about these gases must be true? (There could be more than one correct choice.) A) The internal (thermal) energy of the gas in both flasks is the same. B) The internal (thermal) energy of the gas in the larger flask is greater than the internal (thermal) energy of the gas in the smaller flask. C) The internal (thermal) energy of the gas in the smaller flask is greater than the internal (thermal) energy of the gas in the larger flask. D) The molecules in the larger flask have the same root-mean-square speed as those in the smaller flask. E) The molecules in the smaller flask have the same average kinetic energy per molecule as those in the larger flask.
: A, E
11) An ideal gas undergoes the process a→b→c→a shown in the pV diagram. In this figure, Pa = Pc = 3.60 × 105 Pa, Vb = Vc = 68.00 L, Va = 35 L, and Pb = 5.60 × 105 Pa. How much work is done by the system in this process? A) 2300 J B) 3300 J C) 2800 J D) 3800 J E) 3000 J
: B
13) The process in which heat flows by the mass movement of molecules from one place to another is known as A) conduction. B) convection. C) radiation.
: B
14) A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle, as shown in the pV diagram in the figure. If the process is carried out in a counter-clockwise sense around the enclosed area, as shown on the figure, then the magnitude of the enclosed area represents A) the heat that flows out of the gas. B) the work done on the gas. C) the heat added to the gas. D) the work done by the gas.
: B
17) The water flowing over Niagara Falls drops a distance of 50 m. If all the gravitational potential energy is converted to thermal energy, by what temperature does the water rise? The specific heat of water is 4186 J/kg ∙ K. A) 0.10 C° B) 0.12 C° C) 0.37 C° D) 0.42 C°
: B
19) For the mercury in a thermometer to expand from 4.00 cm3 to 4.10 cm3, what change in temperature is necessary? The mercury has a volume expansion coefficient of 1.80 × 10-4 K-1. A) 400 C° B) 140 C° C) 14 C° D) 8.2 C°
: B
28) Solar houses use a variety of energy storage devices to retain the heat absorbed during the day so that it can be released during the night. Suppose that you were to use a device of this kind to produce steam at 100°C during the day, and then allow the steam to cool to 0°C and freeze during the night. How many kilograms of water would be needed to store 20.0 kWh of energy in this way? The latent heat of vaporization of water is 22.6 × 105 J/kg, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat capacity of water is 4186 J/kg ∙ K. A) 12.4 kg B) 23.9 kg C) 35.7 kg D) 42.6 kg E) 54.2 kg
: B
51) A vertical cylinder, closed at the bottom end, contains 0.0100 mol of ideal gas. It is fitted at the top with a piston that can move freely. The mass of the piston is 14.0 kg and the initial height of the piston above the bottom of the cylinder is 25 cm. What is the temperature of the gas? (R = 8.31 J/mol ∙ K) A) 290 K B) 413 K C) 3620 K D) 405 K E) 500 K
: B
51) The ocean thermal energy conversion project uses the surface water near tropical islands with a temperature of 20°C as the hot temperature reservoir, and the water at some depth, with a temperature of 5.0°C, as the cold temperature reservoir for a heat engine. What is the maximum possible efficiency of an engine running between those two temperatures? A) 4.7% B) 5.1% C) 7.9% D) 15% E) 30%
: B
65) A heat-conducting rod that is wrapped in insulation is constructed with a 0.15-m length of alloy A and a 0.40-m length of alloy B, joined end-to-end. Both pieces have cross-sectional areas of 0.0020 m2. The thermal conductivity of alloy B is known to be 1.8 times as great as that for alloy A. The end of the rod in alloy A is maintained at a temperature of 10°C, and the other end of the rod is maintained at an unknown temperature. When steady state flow has been established, the temperature at the junction of the alloys is measured to be 40° C, and the rate of heat flow in the rod is measured at 56 W. What is the temperature of the end of the rod in alloy B? A) 80°C B) 84°C C) 88°C D) 92°C E) 96°C
: B
73) Two metal rods, one silver and the other copper, are both immersed at one end in a steam chamber at a temperature of 100°C. The other end of each one is in an ice water bath at 0°C. The rods are 5.0 cm long and have a square cross-section that is 2.0 cm on a side. No heat is exchanged between the rods and the surroundings, except at the ends. How much total heat flows through the two rods each minute? The thermal conductivity of silver is 417 W/m ∙ K, and that of copper is 395 W/m ∙ K. A) 20 kJ B) 39 kJ C) 47 kJ D) 49 kJ E) 11 kJ
: B
76) At what temperature would the root-mean-square speed of hydrogen, H2, molecules equal 11.2 km/s (the earth's escape speed)? The mass of a hydrogen atom is 1.67 × 10-27 kg, and the Boltzmann constant is 1.38 × 10-23 J/K. A) 1.01 × 102 K B) 1.01 × 104 K C) 1.01 × 106 K D) 1.01 × 108 K
: B
76) The thermal conductivity of a certain concrete is 0.80 W/m . K and the thermal conductivity of a certain wood is 0.10 W/m ∙ K. How thick would a solid concrete wall have to be in order to have the same rate of heat flow through it as an 8.0-cm thick wall made of solid wood? Both walls have the same surface area and the same temperature difference across their faces. A) 53 cm B) 64 cm C) 71 cm D) 85 cm
: B
83) A heat pump absorbs heat from the atmosphere at a rate of 30 kW. If work is being done to run this heat pump at a rate of 7.7 kW, what is the coefficient of performance (COP) of the heat pump? A) 3.9 B) 4.9 C) 2.9 D) 0.26 E) 22
: B
1) If you wanted to know how much the temperature of a particular piece of material would rise when a known amount of heat was added to it, which of the following quantities would be most helpful to know? A) initial temperature B) specific heat C) density D) coefficient of linear expansion E) thermal conductivity
: B
13) A gas expands from an initial volume of 0.040 m3 to a final volume of 0.085 m3 while its pressure increases linearly with the volume (so that the process follows a straight-line path in a pV diagram) from 110 kPa to 225 kPa. How much work is done by the gas during this expansion? A) 5.2 kJ B) 7.5 kJ C) 7.8 kJ D) 11 kJ E) 12 kJ
: B
14) By what length will a slab of concrete that is originally 18 m long contract when the temperature drops from 24°C to -16°C? The coefficient of linear thermal expansion for this concrete is 1.0 × 10-5 K-1. A) 0.50 cm B) 0.72 cm C) 1.2 cm D) 1.5 cm
: B
16) Oxygen molecules are 16 times more massive than hydrogen molecules. At a given temperature, how do their average molecular speeds compare? The oxygen molecules are moving A) four times faster than the hydrogen molecules. B) at 1/4 the speed of the hydrogen molecules. C) sixteen times faster than the hydrogen molecules. D) at 1/16 the speed of the hydrogen molecules. E) at 1/ the speed of the hydrogen molecules.
: B
16) The second law of thermodynamics leads us to conclude that A) the total energy of the universe is constant. B) disorder in the universe is increasing with the passage of time. C) it is theoretically possible to convert heat into work with 100% efficiency. D) the average temperature of the universe is increasing with the passage of time. E) the entropy of the universe remains constant.
: B
17) A large vat contains 1.000 L of water at 20°C. What volume will this water occupy when it is heated up to 80°C? Water has a volume expansion coefficient of 210 × 10-6 K-1. A) 1.600 L B) 1.013 L C) 0.987 L D) 0.9987 L
: B
19) A 200-L electric water heater uses 2.0 kW. Assuming no heat loss, how many hours would it take to heat the water in this tank from 23°C to 75°C? The specific heat of water is 4186 J/kg ∙ K and its density is 1000 kg/m3. A) 5.0. hours B) 6.0 hours C) 7.0 hours D) 8.0 hours
: B
20) In grinding a steel knife, the metal can get as hot as 400°C. If the blade has a mass of 80 g, what is the minimum amount of water needed at 20°C if the water is to remain liquid and not rise above 100°C when the hot blade is quenched in it? The specific heat of the steel is 0.11 cal/g ∙ C° and the specific heat of water is 1.0 cal/g ∙ C°. A) 22 g B) 33 g C) 44 g D) 55 g
: B
21) The coefficient of linear expansion of copper is 17 × 10-6 K-1. A sheet of copper has a round hole with a radius of 3.0 m cut out of it. If the sheet is heated and undergoes a change in temperature of 80 K, what is the change in the radius of the hole? A) It decreases by 4.1 mm. B) It increases by 4.1 mm. C) It decreases by 8.2 mm. D) It increases by 8.2 mm. E) It does not change.
: B
22) A runner generates 1260 W of thermal energy. If this heat has to be removed only by evaporation, how much water does this runner lose in 15 minutes of running? The latent heat of vaporization of water is 22.6 × 105 J/kg. A) 50 g B) 500 g C) 35 g D) 350 g E) 40 g
: B
25) The coefficient of volume expansion of a certain olive oil is 0.68 × 10-3 K-1. A 1.0-L glass beaker is filled to the brim with olive oil at room temperature. The beaker is placed on a range and the temperature of the oil and beaker increases by 25 C°. As a result, 0.0167 L of olive oil spills over the top of the beaker. Which of the following values is closest to the coefficient of linear expansion of the glass from which the beaker is made? A) 1 × 10-6 K-1 B) 4 × 10-6 K-1 C) 1 × 10-5 K-1 D) 2 × 10-5 K-1 E) 3 × 10-5 K-1
: B
27) The density of water at 0°C is 999.84 kg/m3 and at 4°C it is 999.96 kg/m3. A 1.0-L container, full to the brim with water at 4.0°C is placed in the refrigerator. By the time that the temperature of the water reaches 0.0°C, what volume of water has spilled from the container, assuming that the contraction of the container is negligible? A) 1.1 × 10-7 m3 B) 1.2 × 10-7 m3 C) 1.3 × 10-7 m3 D) 1.4 × 10-7 m3 E) 1.5 × 10-7 m3
: B
28) An athlete doing push-ups performs 650 kJ of work and loses 425 kJ of heat. What is the change in the internal (thermal) energy of the athlete? A) -225 kJ B) -1075 kJ C) 1075 kJ D) 225 kJ E) 276 kJ
: B
29) The coefficient of linear expansion of copper is 17 × 10-6 K-1 and that of steel is 12 × 10-6 K-1. At 12°C a steel rod has a diameter of 2.540 cm and a copper pipe has a diameter of 2.536 cm. If they are heated together to a higher temperature, which one of the following quantities is closest to the common temperature at which the steel rod will fit snugly in the copper pipe? A) 310°C B) 330°C C) 340°C D) 350°C E) 380°C
: B
3) An ideal gas is compressed isobarically to one-third of its initial volume. The resulting pressure will be A) three times as large as the initial value. B) equal to the initial value. C) more than three times as large as the initial value. D) nine times the initial value. E) impossible to predict on the basis of this data.
: B
3) As shown in the figure, a bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. The coefficient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated, it will A) curve upward. B) curve downward. C) remain horizontal, but get longer. D) remain horizontal, but get shorter. E) bend in the middle.
: B