Physics 221 Exam 3
A pure sound notes from a sources make the molecules of air at a location vibrate with simple harmonic motion in accordance with the equation y1 = 0.008 sin (604 π t). What is the frequency of the sound wave?
302 Hz
The temperature on a nice summer day is 84 degrees F. What is the temperature on the absolute (Kelvin) temperature scale?
302 K
A string is clamped at both ends and plucked so it vibrates in a standing wave between two extreme positions as shown by the dashed lines below. If the string has length L and the frequency of oscillation of this mode is f, the speed of the waves on that string is
(2/3) f L
A container with a piston-lid contains an ideal gas at temperature Ti = 27 degrees C (300 K) and a volume V0. The temperature is increased to Tf = 127 degrees C while the pressure is kept constant. What is the new volume?
(4/3) V0
Refer to the heat engine experiment in Studio session 11. The PV diagram for one cycle of the engine is shown below. The path on the diagram connection points (1) and (2) corresponds to which part of the cycle? (a) The air chamber is placed into the ice water. The temperature decreases and the gas contracts. The volume of air in the chamber decrease. (b) A mass is placed on the platform. The weight of the mass increases the pressure at constant temperature. The volume of air in the chamber decrease. (c) The air chamber is placed into hot water. The temperature rises and the gas expands. The volume of air in the chamber increases (d) The mass is removed from the platform. Removing the weight decreases the pressure at constant temperature, The volume of air in the chamber increases.
(c)
The radius of the aorta is ~ 10 mm = 10-2 m and the blood flowing through it has a speed ~ 300 mm/s = 0.3 m/s. A capillary has a radius ~ 4×10-3 mm = 4×10-6 m, but there are literally billions of them. The average speed of blood through the capillaries is ~ 5×10-4 m/s. (i) Calculate the effective cross sectional area of the capillaries and(ii) the approximate number of capillaries.
(i) 0.188 m^2, (ii) 3.75*10^9
A wave travelling in the +x direction is described by the equation y = 0.1 sin (10 x − 100 t), where x and y are in meters and t is in seconds. Calculate (i) the wavelength, (ii) the period, (iii) the speed, and (iv) the amplitude of the wave
(i) 0.63 m, (ii) 0.063 s, (iii) 10 m/s, (iv) 0.1 m
For a sound wave of frequency 440 Hz, what is the wavelength(i) in air (propagation speed, v = 3.3 * 102 m/s)?(ii) in water (propagation speed, v = 1.5 * 103 m/s)?
(i) 0.75 m, (ii) 3.41 m
Organ pipe A is open at both ends and is twice as long as organ pipe B, which is open at one end, as shown. What is (i) the ratio of their fundamental wavelengths λA : λB and (ii) the ratio of their fundamental frequencies fA : fB ?
(i) 1:1 (ii) 1:1
The intensity of sound wave A is 100 times that of sound wave B. Relative to wave B the sound level of wave A is
+20 dB
A traveling wave is described by the equation y(x,t) =( 0.15 m) cos(23.6 x + 280 t ), where x is measured in meter and t in seconds. What is the velocity of this wave in units of m/s? Enter a number with one digit behind the decimal point. Remember that in one dimension the sign of the velocity functions as the direction indicator
-11.9
What is the approximate period of the sound waves shown here? (The speed of sound in air is ~340 m/s.)
0.0037 s
A point source of sound waves emits a disturbance with a power of 50 W = 50 J/s into a surrounding homogeneous medium. What is the intensity of the sound at a distance of 10 m from the source?
0.04 W/m^2
A stone of mass 1.0 kg is dropped into a large lake of water. The stone falls a total distance of 3.0 m. Both the stone and the lake have a temperature of 300 K. Find the changes in entropy of the stone - lake system
0.1 J/K
A 0.5 kg mass oscillates about the equilibrium position on a vertical spring with spring constant 10 N/m. Where is its equilibrium position measured from the unstretched spring position (without the hanging mass)?
0.49 m
Suppose the flow rate of blood in a coronary artery has been reduced to 0.846 times its normal value by plaque deposits, and that the pressure difference across the artery has not changes. By what factor has the radius of the artery been reduced, assuming no turbulence occurs? Enter a number with three digits behind the decimal point
0.959
The third harmonic in a tube with one open end has a frequency of 229 Hz. What is the length of the tube in meter, if the speed of sound is 340.9 m/s? Enter a number with 2 digits behind the decimal point
1.12
When the body requires an increased blood flow rate in a particular organ or muscle, it can accomplish this by increasing the diameter of arterioles on that area. By what factor must the diameter of an arteriole increase to double the volume flow rate of blood, all other factors remaining the same?
1.19
A vibrating source generates a harmonic wave on a string under constant tension. If the power delivered to the string is doubled, by what factor does the amplitude change?
1.41
The temperature in a furnace used to melt Aluminum is 660 degrees C. What is the average kinetic energy of the air molecules in the furnace?
1.93*10^-20 J
A gardener is watering her garden from a hose. With the water pressure full blast holding the hose horizontally she can just reach a distance of 12 m, but needs to water an area up to 16 m away. By what fraction must she reduce the cross-sectional area of the hose, still keeping the hose horizontal, to be able to water this area?
1/4
An intravenous (IV) system is supplying saline solution to a patient at the rate of 0.09 cm3/s through a needle of radius 0.2 mm and length 6.36 cm. What gauge pressure (in Pa) is needed at the entrance of the needle to cause this flow?Assume that the viscosity of the saline solution to be the same as that of water, η = 1.0*10-3 Pa-s, and that the gauge pressure of the blood in the vein is 1500 Pa
10,610
100 dB corresponds to what intensity, in W/m^2?
10^-2 W/m^2
What is the fundamental frequency (in Hz) produced by a pipe of length 1.36 m open at both ends on a day when the speed of sound is 343 m/s? Enter an integer
126
Assume that a naked human body has a surface area of 1.5 m 2 and a surface temperature of 32 degrees C. If the surroundings are at a temperature of 16 degrees C, calculate the net rate of heat loss by the body due to radiation. Assume an emissivity of 1
143 W
5 moles of a monatomic gas has its pressure increased from 105 Pa to 2*105 Pa. This process occurs at a constant volume of 0.1 m^3. Determine the change in the internal energy of the gas
15000 J
A rope has a mass of 3 kg and a length of 11.6 m. It is fixed at both ends. If the frequency of the first harmonic on this rope is 1.06 Hz, what is the tension of this rope in N? Enter a number with one digit behind the decimal point
156.4
How much thermal energy (in kcal) is required to change a 22 g ice cube from a solid at - 1.6 degrees C to steam at 13.8 degrees C above boiling?
16
A 1 kg block of aluminum is heated at atmospheric pressure such that its temperature increases from 22 degrees C to 40 degrees C. What is the change in the internal energy (in J) of the block of aluminum?The specific heat of aluminum is 9*102 J/(kg K). Enter an integer
16,200
The decibel level of a sound is 72.3 dB. What is the intensity of the sound in nW/m2?1 nW = 10-9 W Enter a number with 1 digit behind the decimal point
16,982.4
If you double the radiating surface area of a star while keeping its temperature constant, its power output increases by a factor of
2
A thermodynamic system undergoes a process in which its internal energy decreases by 1,628 J.If at the same time 787 J of thermal energy is transferred to it, how much work (in J) is done by the system?
2,415
A tank having a volume of 0.1 m^3 contains helium gas at 150 atm. How many balloons can the tank blow up, if each filled balloon is a sphere of radius 0.1 m at an absolute pressure of 1.2 atm? Enter an integer
2,984
You are watching a mass oscillate on a spring. The initial amplitude is 40 cm. The amplitude halves after 10 s. How long does it take for the amplitude of the oscillation to decrease to 10 cm?
20 s
A refrigerator has a coefficient of performance equal to 9.6. If the refrigerator absorbs 211 J of thermal energy from a cold reservoir in each cycle, find the work done on the system each cycle (in J). Enter a number with one digit behind the decimal point
22
A Venturi tube may be used as a fluid flow meter. If the fluid flow rate in m^3/s is 2.4 * 10-3 and the radius R1 = 2 *10-2 m of the inlet tube is 2 times the radius R2 of the outlet tube, and the fluid is water (ρ = 1000 kg/m^3), find the pressure difference P1 - P2 in units of kPa. Enter a number with one digit behind the decimal point
27.4
Heat is added at a rate of 10.0 kJ/min to a 0.5 kg solid sample starting at t = 0 min. What is the melting temperature of the sample? Note the units of the answers!
283 K
Pure sound notes from two sources make the molecules of air at a location vibrate simple harmonically in accordance with the equations y1 = 0.008 sin (604 π t) and y2= 0.007 sin (610 π t), respectively. The number of beats heard by a person at the location will be
3
Two dice are thrown. Let the macrostate be the sum of the two numbers on the top faces. What is the multiplicity of the macrostate "4"?
3
An ideal reversible engine takes in 5 kJ of energy via heat transferred in from a 500 K burner and exhausts heat at 300 K during each closed cycle in the PV plane.The amount of heat exhausted at 300 K each cycle is
3 kJ
Your friends decide to play a prank on you and lock you in a room with two speakers making an incessant hum at 680 Hz. Which of the following locations would deafen the hum the most?(Take the speed of sound to be 340 m/s.)
3.00 m away from speaker A; 3.75 m away from speaker B
A standing wave is established on a 1.2 m long string fixed at both ends. The string vibrates in four segments when driven at 120 Hz. What is the fundamental frequency?
30 Hz
On a humid summer day, perspiration does not cool you off much. Why?
The air is almost saturated with water vapor and there is almost no net evaporation
Which one of the following is Bernoulli's equation not involved in explaining?
The buoyant force on a floating iceberg
When you sit facing a campfire outdoors, your face feels quite warm because
The campfire is radiating heat towards your skin
Compare the flight of two golf balls given the same impulse by the club. Which ball will travel a larger distance?
The dimpled ball
A gas is in a container with a piston lid and is taken from thermodynamic state, 1, to a new thermo-dynamic state, 2, by several different paths, A, B, and C, in the P-V plane. The internal energy of the gas increases during the process. The internal energy change is largest for path
The internal energy change is the same for the three paths
The longer the wavelength of a sound wave
The lower is its pitch
Superman comes to the rescue of a runaway train car (without the locomotive) that is rolling downhill by pushing on the train car to bring it to a stop. Assuming that the standard laws of physics hold, as Superman is slowing down the train car,
The magnitude of force that Superman exerts on the train car is equal to the force that the train car exerts on Superman
In simple harmonic motion
The magnitude of the acceleration is greatest at the maximum displacement
You fill two identical mugs with coffee, but the coffee in one mug is at a higher temperature than that in the other mug. You place the two mugs simultaneously in a microwave oven and turn it on briefly. As a result, you add 1 Joule of thermal energy to each mug. Which mug experiences the larger increase in entropy (if any)?
The mug containing the colder coffee experiences the larger increase in entropy
Which of the statements below is wrong?
The net force acting on the pendulum bob is F = -mgsinθ. The period increases with amplitude because this force increases faster than harmonic restoring force F= -mgθ
The maintenance of the life cycle depends on
The presence of a source and a sink of energy
Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. A hemoglobin molecule moves from the wider region into the narrower region. What happens to the pressure acting on the molecule as it moves from the wider into the narrower region?
The pressure decreases
Suppose that there is a partial blockage of the aorta, which normally pumps about 5 L of blood per minute. If the diameter of the aorta were reduced by 30%, what increase in blood pressure gradient would be needed to obtain the normal flow rate? (Assume that Poiseuille's law applies.)
The pressure gradient would have to increase by a factor of 4.2
Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. A hemoglobin molecule moves from the narrow region into the wider region. What happens to the pressure acting on the molecule as it moves from the narrow to the wider region?
The pressure increases
Water is flowing smoothly through the pipe shown in the diagram
The pressure is lowest in section B
The speed of sound waves having a frequency of 256 Hz compared to the speed of a sound wave having a frequency of 512 Hz is
The same
Suppose you have an aquarium. You have a solid plastic decoration and a rock of about the same volume but the rock has twice the mass. Both are totally submerged in the water. The buoyant force on the plastic object is about
The same as that on the rock
A sinusoidal force with a given amplitude is applied to an oscillator. To maintain the largest amplitude oscillation, the frequency of the applied force should be
The same as the natural frequency of the oscillator
When blood flows into an aneurysm
The speed decreases and the pressure increases
A pitcher contains 0.50 kg of liquid water and 0.50 kg of ice at 0°C. You let heat flow into the pitcher until there is 0.75 kg of liquid water and 0.25 kg of ice. During this process
The temperature of the ice‐water mixture remains the same
The liquid level in a glass thermometer rises as the temperature increases because
The volume expansion coefficient of glass is less than that of the liquid
In your dorm room you watch the Vols play in an out-of-town game. It is a cliff hangers and the winner will be determined in the last few seconds of play. Everybody is taking their bathroom break right after the game ends. As the toilets flush and hands are washed, the faucet pressure is noticeably reduced, even though the supply pipe to the rooms can carry all the water needed. Why?
The water has to speed up in the supply pipe and therefore the pressure drops in the pipe
A 200 Hz sound wave has a measured wavelength of 1.675 m.Which of the following statements are true? You can choose more than one statement
The wavelength of the 400 Hz wave is ~ 80 - 85 cm The speed of the 200 Hz wave is ~335 m/s
Which of the following assumptions is not made in the derivation of Bernoulli's equation?
There is negligible gravity
How will the wavelengths of the harmonics of an open tube compare with those of a string of the same length L?
They will be the same
Why does heat, of itself, not flow from a cold to a hot object, if it is allowed by Newton's laws?
This would require a large departure from equilibrium, which is extremely unlikely
A sine wave and a square wave cannot have the same
Tone quality
It is possible for heat to flow across vacuum
True
A water pump generates a constant flow Q, which is causing a turbulent spray (Reynolds number R = 3200) out of this cylindrical nozzle: Which of the following three nozzles could be substituted to achieve a streamline flow (R < 2000)?
Tube I and III
When a car drives down a street full of fallen leaves, the leaves swirl around behind the car. What kind of flow is present behind the car?
Turbulent flow
We flip a fair coin 10 times. Define a macrostate to be the number of heads. Define each microstate as a a particular sequence of heads and tails. Some microstates for coin flips are listed below. "H" stands for heads and "T" stands for tails. Rank the microstates from most likely to least likely to occur
VI) = III) = II) = I)
Sound does not pass through
Vacuum
Data: cice = 0.50 cal/(g degrees C) cwater = 1.00 cal/(g degrees C) csteam = 0.48 cal/(g degrees C) L(ice-water) = 80 cal/g L(water-steam) = 540 cal/g Which requires the most energy?
Vaporize 0.5 gram of water at T = 100 degrees C
In studying tornado formation, it is thought that water condensing is a very important driving mechanism for the violent storm because
Water condensing releases a lot of energy into the environment
Two carts A and B are moving towards each other as shown in the diagram. They collide and come to rest at the point of impact. From this observation we can conclude that the carts
Were moving with momenta equal in magnitude and opposite in direction
Your dryer is broken, so you have to hang your wet clothes from the washing machine outside to dry. Under which conditions would your clothes dry fastest?
When it is 75°F with 50% relative humidity
In a popular classroom demonstration, a cotton ball is placed in the bottom of a strong test tube. A plunger fits inside the tube and it makes an air-tight seal. It is then pushed down very rapidly, and the cotton flashes and burns. This happens because
When the air gets compressed its temperature increases
Heat is the transfer of disordered energy from one system to another. Is it possible for heat to enter a system while the temperature of the system does not change?
Yes
Can an object's velocity change direction when its acceleration is constant?
Yes, this is possible, and a rock thrown straight up is an example
The P-V diagram below shows six curved paths (connected by vertical paths) that can be followed by a gas. Which two of them should be part of a closed cycle if the net work done by the gas is to be at its maximum positive value?
c and e
The SI units for viscosity are
kg/(m-s)
If you double the wavelength λ of a wave on a string under fixed tension, what happens to the wave speed v and the wave frequency f?
v is unchanged and f is halved
The four things that affect the amount of water flowing through a hose are
water viscosity, hose length, inlet and outlet pressure difference, and hose diameter
Position, velocity and acceleration of an oscillating mass on a spring are shown as a function of time. What is the frequency of the oscillations?
~0.4/s
You hear the sound of the ring of a distant cannon 3 seconds after seeing the flash. How far are you from the cannon?
~1000 m
Find the natural frequency of vibration of the salt molecule NaCl given its effective mass of 13.9 atomic mass units and a spring constant of 100 N/m
~1013 Hz
Measure the frequency or period of a 0.2 kg mass oscillating on a spring. Click on the link below. What is the spring constant of this spring?
~16.3 N/m
Position, velocity and acceleration of an oscillating mass on a spring are shown as a function of time. If the mass is 1 kg, what is the spring constant in N/m?
~6
An ideal gas in a closed container with a piston lid is taken from thermodynamic state, 1, to a new thermodynamic state, 2, by an isothermal path as shown below in the P‐V plane. Let ΔU be the internal energy change during this process, ΔQ be the heat transferred into the gas, and ΔW be the work done by the gas
ΔW is positive, ΔQ is positive and ΔU = 0
By how much does the entropy of 100 g of water at 0 o C change if the water is slowly converted into ice at 0 o C? The latent heat of fusion is 80 kcal/kg
‐0.029 kcal/K
Let the speed of sound be 340 m/s. A source emits a sound of 276 Hz. It is moving towards the right with a speed of 39 m/s and approaching an observer who is moving towards the left with a speed of 37 m/s. what is the frequency heard by the observer? Enter an integer.
346
Suppose you have a tube 0.25 m long with a speaker at one end and with the other end open. If you gradually increase the frequency of the speaker from zero at about what approximate frequency will you hear the first resonance?
350 Hz
Data: cice = 0.50 cal/(g degrees C) cwater = 1.00 cal/(g degrees C) csteam = 0.48 cal/(g degrees C) L(ice-water) = 80 cal/g L(water-steam) = 540 cal/g How much heat is given off if 0.5 kg of steam at 373 K is converted into ice at 273 K?
360 kcal
A stationary source S generates circular outgoing waves on a lake. The wave speed is 5.0 m/s and the crest-to-crest distance is 2.0 m. A person in a motorboat heads directly toward S at 3.0 m/s. To this person, the frequency of these waves is:
4 Hz
In the cyclic process on an ideal gas shown in the adjoining PV diagram, what is the net work done by the gas during the cycle?
4 PV
The mechanical energy of a mass-spring system is 0.354 J. If the force constant of the spring of 295 N/m and the mass is 0.38 kg, what is the amplitude of the oscillatory motion in cm?
4.9
The temperature in degrees F is -382. What is the temperature in K? Enter an integer
43
A piano tuner detects 3 beats per second when she is tuning a string to a tuning fork of frequency 440 Hz. When she tightens the string, which increases the frequency of the string, the frequency of the beats initially goes down, and as she keeps increasing the frequency of the string, the frequency of the beats starts to increase. What was the original frequency of the string?
437 Hz
A particular violin string plays at a frequency of 440 Hz. If the tension is increased by 8.0%, what is the new frequency?
457 Hz
A 2 kg block of aluminum is heated at atmospheric pressure such that its temperature increases from 17 degrees C to 43 degrees C. What is the change in the internal energy (in J) of the block of aluminum? The specific heat of aluminum is 9*102 J/(kg K). Enter an integer
46,800
When a tuning fork is sounded together with a 492 Hz tone, a beat frequency of 2 Hz is heard. Then a small piece of putty is struck to the tuning fork, and the tuning fork is again sounded along with the 492 Hz tone. The beat frequency decreases. What is the frequency of the tuning fork?
494 Hz
Ice initially at -20 degrees C is to be turned into steam at 130 degrees C. To figure out how much heat is required, how many separate terms will there be (i.e. ΔQ = c*m*ΔT, ΔQ = m*LV, and ΔQ = m*Lf)?
5
A 0.3 kg block of copper is heated at atmospheric pressure such that its temperature increases from 17 degrees C to 64 degrees C. How much heat (in J) is absorbed by the block of copper? The specific heat of copper is 0.092 (kcal/(kg degrees C)) 1 kcal = 4186 J Enter an integer
5,430
A box with a total surface area of 1.2 m2 and a wall thickness of 4 cm is made of an insulating material. A 10 W electric heater inside the box maintains the inside temperature at 15 degrees C above the outside temperature. What is the thermal conductivity of the insulating material in units of kcal/(s degrees C m)?
5.3 10^-6
At which temperature do the molecules of an ideal gas have 3 times the kinetic energy they have at 32 degrees F?
546 degrees C
Beats are produced when two tuning forks, one of frequency 240 Hz and another of frequency 246 Hz are sounded together. The frequency of the beats is
6 Hz
A train whistle is blown by the driver who hears the sound at 644 Hz. If the train is moving away from the station at 25.0 m/s, what will the whistle sound like to a person waiting at the station? Take the speed of sound to be 340 m/s
600 Hz
By how much does the entropy of 100 g of water at 100 degrees C change if the water is very slowly converted into steam at 100 degrees C?The latent heat of vaporization of water is 540 kcal/kg = 2260 kJ/kg.
606 J/K
Ethyl alcohol boils at 172 degrees F. What is Celsius equivalent of this temperature?
78 degrees C
A nozzle with a radius of 0.18 cm is attached to a garden hose with a radius of 1.33 cm. If the speed of the water in the hose is 1.46 m/s, what is the speed of the water in the nozzle in m/s? Enter a number with two digits behind the decimal point.
79.71
Consider a tractor driving across a field that has undulations at regular intervals. The distance between the bumps is about 4.2 m. Because of safety reasons, the tractor does not have a suspension system but the driver's seat is attached to a spring to absorb some of the shock as the tractor moves over rough ground. The natural frequency of the driver and the seat is f = 2 Hz. At what speed does the drive become dangerous?
8.4 m/s = 18.8 mph
What is the maximum coefficient of performance of a heat pump that takes heat from outdoors at a temperature of -12.1 degrees C and delivers it indoors at a temperature of 21.4 degrees C. Enter an number with one digit behind the decimal point.
8.8
An alarm clock makes a sound that has intensity 60 dB at a distance of 1 m. What is the sound intensity of 100 such clocks which are all 1 m away?
80 dB
A microwave oven is rated at 1000 W. At sea level, how long will it take to bring a cup of water (250 ml) to boil from room temperature (20 °C)? Assume the specific heat capacity of the cup itself is negligible
84 s
A 0.500 kg mass is attached to a spring of constant 150 N/m. A driving force F(t) = (12.0 N)cos(ωt) is applied to the mass, and the damping coefficient b is 6.00 Ns/m. What is the amplitude of the steady-state motion if ω is equal to half of the natural frequency ω0 of the system?
9.7 cm
The specific heat of aluminum is 0.215 kcal/(kg degrees C). A 3 kg block of aluminum is heated from 10 degrees C to 150 degrees C. What is the change in the internal energy (in units of kcal) of the block? Enter an integer.
90
Calculate the magnitude of rate of heat flow (in kJ/s = kiloWatts) by conduction through 1.2 cm thick Aluminum plate with an area of 4.1 m^2, if the temperature difference between the two sides is 13.4 degrees C. Thermal conductivity of Al: 4.9*10-2 (kcal/sec)/(degrees C m) 1 kcal = 4186 J Enter an integer.
939
What is vrms (root mean square speed) of a He atom in m/s at 153 K temperature? Enter an integer
977
Gas in a container is at a pressure of 1.7 atm and a volume of 6.2 m^3. What is the work (In kJ) done by the gas if it expands at constant pressure to a volume 12 m^3? Use 1 atm = 101 kPa. Enter an integer
996
A gas is in a container with a piston lid and is taken from thermodynamic state, 1, to a new thermo-dynamic state, 2, by several different paths, A, B, and C, in the P-V plane. The internal energy of the gas increases during the process. The work done by the gas is largest for path
A
Suppose you work in the E.R. and a choking patient comes in with their trachea half obstructed. (The diameter is half of what it was before the obstruction.) You manage to correct the problem and send them on their way safely, explaining that such obstructions are particularly dangerous because
A half - blocked airway passes only 1/16 the regular amount of air
Fluid is flowing from left to right through the pipe. Points A and B are at the same height, but the cross-sectional areas of the pipe differ. Points B and C are at different heights, but the cross-sectional areas are the same. Rank the pressures at the three points, from highest to lowest.
A, B, C
We observe the harmonic motion of an object. Its position as a function of time shown in the graph below is given by x = 1* cos(π t), where x is measured in meter and t is measured in seconds. What are the amplitude (A), the period (T), and frequency (f) of the motion?
A: 1 m, T: 2 s, f: 0.5 Hz
Which sounds travel the fastest through air?
All sound travels at the same speed through air
At a given temperature
All the molecules in a gas have the same average kinetic energy
The Doppler effect is characteristic of
All traveling waves
A star with a surface temperature of 6000 K appears yellow in color. A star with a surface temperature of 4000 K will
Appear reddish on color
Sound waves
Are longitudinal waves
Heat is added at a rate of 10.0 kJ/min to a 0.5 kg solid sample starting at t = 0 min. A temperature versus time diagram is shown. In which region(s) is the liquid phase present?
B and C
When I bake a sweet potato in the oven, I always put it on a thin sheet of aluminum foil. This is because sometimes the potato exudes a sugary juice that burns and makes a hard-to-clean-up mess if it drips on the bottom of the oven. When I'm ready to take the potato out of the hot (400 degrees F) oven after an hour of cooking, I find I can pick up the aluminum foil with my bare hands without getting burned. Why?
Because the aluminum foil has a low specific heat and not much mass, so even at a high temperature it doesn't have a lot of thermal energy in it to burn me
You drop an object from a bridge and simultaneously, you throw a-other object downwards at 10 m/s. As the objects are falling, which object has the larger acceleration? (Ignore air resistance.)
Both objects have the same acceleration
You need to loosen a very tight bolt. You have one wrench and you exert maximum force. Which configuration shown below gives you maximum chance of success?
C
A simple pendulum of length L oscillates back and forth 10 times per second. By what factor do you have to change its length to make it oscillate back and forth 20 times per second?
Decrease the length by a factor of 4
In any process, the maximum amount of heat that can be converted into mechanical energy
Depends on the intake and exhaust temperatures
In the figure below, two point sources S1 and S2, which are in phase, emit identical sound waves of wavelength 2.0 m. If L1 = 39 m and L2 = 36 m, what type of interference occurs at point P?
Destructive interference
In the figure below, two point sources S1 and S2, which are in phase, emit identical sound waves of wavelength 2.0 m.If L1 = 39 m and L2 = 36 m, what type of interference occurs at point P?
Destructive interference
Why are good thermal conductors generally good electric conductors also?
Electron motion is responsible for determining both properties
In order to do a positive amount of work you must
Exert a force and move in the direction of the force
The total entropy of the universe is always increasing. So, when water freezes, the entropy of the water is increasing
False
The four strings of a musical instrument are all made of the same material and are under the same tension, but have different thicknesses. Waves travel
Fastest on the thinnest string
Referring to the graph below, which phase has the smallest specific heat capacity?
Gas
A car travels over a dirt road that contains a series of equally spaced bumps (a so-called "washboard" road). While traveling at a given speed the driver experiences a very jarring ride. When the driver drives at a higher speed, however, the ride gets smoother. That is because
Going faster in the car forces the suspension to oscillate at a frequency higher than its natural frequency
A heat engine extracts usable work by permitting
Heat to flow from a hotter object to a colder object
In a mixture of hydrogen, oxygen, and nitrogen gases at a given temperature, the molecules having the greatest average speed are those of
Hydrogen
Pressure vs. volume graphs for a certain gas undergoing five different cyclic processes are shown to the right. During which cycle does the gas do the greatest positive work?
IV
Orange growers in Florida spray their trees with water when they expect a freeze. Why does this work?
If a mixed phase of water and ice is present, the temperature does not drop below 0 degrees C
In the figures (a), (b), (c), (d) and (e) below, S is a source of sound of real frequency f and L is a listener.The speeds of the source and the listener are equal (v) in all cases except in (e) where the source is at rest and the listener is moving with speed v (as in the other cases). There is no wind. From the statements below, pick out the wrong statement.
In the case shown in fig (d) the apparent frequency as heard by the listener is less than the real frequency of the source
One mole of monatomic gas undergoes an adiabatic process (i.e. one where no heat enters or leaves the system). A pressure versus volume graph of the process is shown to the right. The initial and final volumes are given in the table below. What are the initial and final temperatures?
Initial T: 361 K; final T: 144 K
In any process, the maximum amount of mechanical energy that can be converted into thermal energy
Is 100%
You have an empty 20 oz. soda bottle and you blow air over the opening to excite a fundamental standing wave. Now, you slice off the bottom of the bottle (it's plastic) without changing its length very much. You blow over the opening and excite a fundamental standing wave in the bottle with its bottom end open. The frequency of the standing wave in the second case
Is higher than that in the first case
If a viscous fluid flows steadily in a pipe, the fluid speed
Is least near the pipe wall but increases toward the center
A string is clamped at both ends and then plucked so that it vibrates in a standing mode between two extreme positions a and c. Let upward motion correspond to positive velocities. When the string is in position b, the instantaneous velocity of points along the string
Is zero, positive, or negative, depending on the position along the string
If the absolute temperature of a gas is halved, what happens to the average (root‐mean‐square or RMS) speed, square root of < v^2 >, of the gas molecules?
It decreases to 1/square root of 2 the original average speed
A gas, confined to an insulated cylinder, is compressed adiabatically (and reversibly) to half its original volume. Does the entropy of the gas increase, decrease, or remain unchanged during this process?
It remains unchanged
If no external forces are acting on a moving object
It will continue moving with the same velocity
Water pours gently from an open hose because it
Lost energy throughout its trip to the hose end
The volume of a gaseous sample is increased from V1 to V2 in three different ways. A-->B: isobaric process A-->C: isothermal process A-->D: adiabatic process Then the work done by the gas is
Maximum in the isobaric process
Two thermometers, one calibrated in degrees F and one in degrees C, are used to measure the same temperature. The numerical reading on the Fahrenheit thermometer
May be equal, higher or lower than that on the Celsius thermometer, depending on the temperature
A square metal plate with edge length L 0 (area A = L 0 2) is heated so that it expands and its new edge length is 1.01 L 0. What is its new area?
More than (1.01) L 0 2
When a car is at rest, its horn emits a sound wave of wavelength 0.55 m. A person standing in the middle of the street hears the horn with a frequency of 560 Hz. If the speed of sound is 330 m/s, should the person jump out of the way?
No
A hypothetical engine operates in a cycle taking in 10,000 J from a hot reservoir and 5000 J from a cold reservoir. In the cycle it performs 15,000 J of work. Such an engine
Obeys the first law but violates the second law of thermodynamics
A ball is thrown straight upward. It rises in the air and then falls back to earth. Neglect friction.
On the way up, kinetic energy is converted to potential energy
Assume we can change the equilibrium state of a system via two different processes. Assume that the initial and the final state are the same. Which of the quantities ΔU, ΔQ, ΔW, and ΔT must be the same for the two processes?
Only ΔU and ΔT
Which of the following statements is false?
Plaque deposit on an artery or arteriole wall causes an increase in local blood pressure and can lead to bursting of that vessel
Rockets receive their forward propulsion through
Pushing against the exhaust
Dimples on a golf ball hit without spin
Reduce drag
A simple pendulum consists of a point mass m suspended by a massless, unstretchable string of length L. If the mass is doubled while the length of the string remains the same, the period of the pendulum
Remains unchanged
A refrigerator
Removes heat from a cold region and delivers the more heat to a hotter region
The _______ the temperature difference between hot and cold, the smaller the fraction of heat you can divert and transform into __________.
Smaller; work