PHYSICS 221 FINAL UTK 2019
A container with a piston-lid contains an ideal gas at temperature Ti = 27 oC (300 K) and a volume V0. The temperature is increased to Tf = 127 oC while the pressure is kept constant. What is the new volume?
(4/3) V0
(A) Can two force vectors of unequal magnitude sum to zero net force? (B) Can three force vectors of equal magnitude sum to zero net force?
(A) no, (B) yes
A block slides on a track from A to B to C to D. The section from A to B to C is frictionless, but for the section from C to D the coefficient of friction is not zero. Is the block's mechanical (ordered) energy increasing, decreasing, or constant in (a) region AB, (b) region BC, and (c) region CD?
(a) constant (b) constant (c) decreasing
A block slides on a track from A to B to C to D. The section from A to B to C is frictionless, but for the section from C to D the coefficient of friction is not zero.Is the block's mechanical (ordered) energy increasing, decreasing, or constant in (a) region AB, (b) region BC, and (c) region CD?
(a) constant (b) constant (c) decreasing
An object is dropped from rest at t = 0 into a viscous fluid. Which of the following best describes the object's speed as a function of time?
(b)
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 m2, (ii) 3.75*109
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
A cart can move to the right or left along a horizontal track (the positive part of the x axis) as shown in the figure below. Neglect friction. A force is applied to the cart. Choose an appropriate force versus time graph for each statement below. (i) The cart moves toward the right (away from the origin) with constant velocity. (ii) The cart moves toward the right and is speeding up at a steady rate (constant acceleration). (iii) The cart moves toward the left and is speeding up at a steady rate (constant acceleration). (iv) The cart moves toward the right, speeds up and then slows down.
(i) E, (ii) A, (iii) B, (iv) G
0.5 kg of ice slowly melts. The latent heat of fusion is 80 kcal/kg. By how much does the entropy of the ice change?
+0.147 kcal/K
Suppose a woman does 500 J of work and 9500 J of heat transfer occurs into the environment in the process. What is the decrease in her internal energy, assuming no change in temperature or consumption of food?
-10000 J
A centrifuge in a medical laboratory rotates at an angular speed of 3600 rev/min. When switched off, it rotates 50 times before coming to rest. What is the constant angular acceleration of the centrifuge?
-226.2/s2
A car was running with velocity 90 m/s. When driver saw a baby on the road, he applied brake and the car stopped after 3 seconds. What is the average acceleration of the car?
-30 m/s^2
A boy holds a 40 N weight at arm's length for 10 s. His arm is 1.5 m above the ground. The work done by the force of the boy on the weight while he is holding it is
0.
Vector A = -3.00 i + 3.00 j and vector B = 3.00 i + 4.00 j. What is vector C = A + B ?
0.00 i + 7.00 j
When the temperature of a certain solid, rectangular object increases by ∆T, the length of one side of the object increases by 0.010% = 1.0*10^-4 of the original length. The increase in volume of the object due to this temperature increase is
0.030% = 3.0*10^-4 of the original volume.
The pressure of a gas in a cylinder with a movable piston is increased from 45 kPa to 90 kPa. If the temperature is held constant, and the initial volume of the gas in the cylinder is 0.5 m3, what is the final volume of the gas?
0.25 m3
A cat leaps to catch a bird. If the cat's jump was at 60.0° off the ground and its initial velocity was 2.74 m/s, what is the highest point of its trajectory?
0.29 m
Consider a 100 kg father and his 20 kg girl. They decide to enjoy balancing on a seesaw, which is a uniform board 4 m long and pivoted exactly at its center. If girl sits at the seesaw's end (2m from the center), how far from the center on the other side should the father sit?
0.4 m
The efficiency of this heat engine is
0.40
Another scheme to catch the roadrunner has failed and a safe falls from rest from the top of a 30.0 m high cliff toward Wile E. Coyote, who is standing at the base. Wile first notices the safe after it has fallen 15 m. How long does he have to get out of the way?
0.72 s
As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest?
1
Three identical oscillators have the same amplitude A and the same angular frequency All three oscillate in simple harmonic motion given by x = A cos The three oscillators have different phase angles however. Rank the three oscillators in order of their displacement x at t = 0, from most positive to most negative. 1. Oscillator with = 0 2. Oscillator with = pi/4 3. Oscillator with = pi/2
1 (MOST POSITIVE) 2 3 (MOST NEGATIVE)
In how many of the following situations does the car have a westward acceleration? -- The car travels westward at constant speed. -- The car travels eastward and speeds up. -- The car travels westward and slows down. -- The car travels eastward and slows down. -- The car starts from rest and moves toward the east.
1 (The car travels westward and slows down)
An apple at rest weighs 1 N. Now assume the same apple is in free fall near the surface of Earth. Neglect friction. The net force on the apple while it is in free fall is
1 N
A 170 Hz sound wave in air has a wavelength of 2.0 m. The frequency is now doubled to 340 Hz. What is the new wavelength?
1.0 m
What is the wavelength of this standing wave?
1.0 m
A rubber ball experiences the force shown in FIGURE as it bounces off the floor. What is the impulse on the ball?
1.2 Ns
Two masses are located on the x-axis. Mass m1 = 4 kg is located at x = -50 cm and mass m2 = 6 kg is located at x = 20 cm. What is the moment of inertia of the system about the z-axis in units of kgm2.
1.24
A cylinder of gas has a frictionless but tightly sealed piston of mass M. The gas temperature is increased from an initial 27°C to a final 127°C. What is the final-to initial volume ratio Vf/Vi?
1.33
A simple pendulum has a period of 2.8 s. What is its length?
1.95 m
A motor is used to lift an object weighing 15 N a distance of 2 m in 3 seconds. Assuming no conversion of ordered into thermal energy, what is the power output of the motor?
10 W
You live in an apartment directly above an open-air tavern and you possess a really, really long and sturdy straw. You plan to steal beer by leaning out of your apartment window and, when the beer-drinkers are not looking, sticking your straw into beer glasses and sucking on the straw. Assuming you can create a perfect vacuum when you suck on the straw, for this plan to have a chance of working, the height difference between you and the beer must be less than approximately what distance? (Assume the density of beer is equal to the density of water and the pressure is 1 atm = 101 kPa.)
10 m
For this sinusoidal wave, what is the frequency?
100 Hz
Use g = 10 m/s2. An airplane is flying horizontally over level ground. It has an altitude of 500 m and a velocity of 100 m/s. As the airplane passes directly above a cross marked on the ground, an object is released. How far away from the cross will the object land?
1000 m
A 500 N weight sits on the small piston of a hydraulic machine in equilibrium. The small piston has area 2.0 cm2. If the large piston has area 40 cm2, how much weight does the large piston support?
10000 N
A pulley has an initial angular speed of 12.5 rad/s and a constant angular acceleration of 3.41 rad/s 2 . Through what angle does the pulley turn in 5.26 s?
113 rad
Assume g = 10 m/s2. A football's mass is 0.45 kg. If you did the 60 J of work on the football, while throwing it straight up, how high would it go?
13.3 m
Two blocks of mass M and 3 M are placed on a horizontal frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord holding them together is burned, after which the block of mass 3 M moves to the right with a speed of 5 m/s. What is the speed of the block of mass M?
15 m/s to the left
A 1200 kg car's speed changes from 5 m/s to 20 m/s in 4 s. By what factor does its kinetic energy change during those 4 s.
16
Suppose you are changing a car tire and loosening a lug nut. You weigh 800 N and stand on the end of a horizontal 2 m long wrench. How much torque do you exert on the lug nut?
1600 Nm
A cheerleader lifts his 50 kg partner three times straight up off the ground a distance of 1.1 m before releasing her. How much work does he do lifting her 3 times? Use g = 10 m/s2.
1650 J
A person weighing 900 N is standing on snowshoes. Each snowshoe has area 2500 cm 2 and has negligible weight. What pressure does this person's weight exert on the snow?
1800 N/m^2
A 2 kg block of wood is floating in water. What is the magnitude of the buoyant forceacting on the block?
19.6 N
A bicycle's wheels have a radius of 33 cm. The bicycle is traveling at a speed of 6.5 m/s. What is the angular speed of the front tire?
19.7 rad/s
A 1 kg rock is suspended by a massless string from one end of a meter stick at the 0 cm mark. What is the mass m suspended from the meter stick at the 75 cm mark if the system is balanced?
2 kg
For this sinusoidal wave, what is the wavelength?
2 m
A 10-kg block is pushed across a horizontal surface with a horizontal force of 30 N against a friction force of 10 N. The acceleration of the block is
2 m/s 2 .
Suppose the circumference of a bicycle wheel is 2 m. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be
2 m/s.
The period of this wave is
2 s
A 2.0-kg mass moving at 5.0 m/s suddenly collides head-on with a 3.0-kg mass at rest. If the collision is perfectly inelastic, what is the speed of the masses just after the collision?
2.0 m/s
A stone is thrown directly upward with an initial speed of 8.5 m/s from a height of 6.7 m. After what time interval (in s) does the stone strike the ground? (Recall: the magnitude of g = 9.8 m/s 2 .)
2.32 s
A fan rotating with an initial angular velocity of 1000 rev/min is switched off. In 2 seconds, the angular velocity decreases to 200 rev/min. Assuming the angular acceleration is constant, how many revolutions does the blade undergo during this time?
20
Christina throws a javelin into the air. As she propels it forward from rest, she does 270 J of work on it. At its highest point, its gravitational potential energy has increased by 70 J. What is the javelin's kinetic energy at this point?
200 J
During one cycle, an automobile engine with an efficiency of 20% takes in 10,000 J of heat. How much work does the engine do per cycle?
2000 J
Use g = 10 m/s2. A block with a weight of 2 N slides across a flat surface with a speed of 15 m/s. What is the kinetic energy of the block?
22.5 J
During one cycle, an automobile engine takes in 12,000 J of heat and discards 9000 J of heat. What is the efficiency of this engine?
25%
Blood is pumped from the heart at a volume flow rate of 5.0 liter/min into the aorta (of radius 1.0 cm). Determine the speed of blood through the aorta.
26.5 cm/s
A 750 kg automobile is traveling horizontally with speed 20.0 m/s. What is the automobile's new speed after an additional 150000 J of net work has been done on the car?
28.3 m/s
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
A girl pulling a sled exerts a 20 N force horizontally for 40 s. How much power does she generate while moving the sled 60 m?
30 W
With the temperature held constant, the piston of a cylinder containing a gas is pulled out so that the volume increases from 0.1 m3 to 0.3 m3. If the pressure of the gas was 90 kPa, what is the final pressure?
30 kPa
A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J. What is the efficiency of this process?
30%
The following pairs of temperatures represent the temperatures of hot and cold reservoirs for heat engines. Which heat engine has the highest possible efficiency?
300°C, 30°C
Substance A has a density of 3.0 g/cm3 and substance B has a density of 4.0 g/cm3. In order to obtain equal masses of these two substances, the ratio VA/VB of the volume of A to the volume of B has to be equal to
4 : 3
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
A person walks first at a constant speed of 6 m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 4 m/s. What is her average speed over the entire trip? Hint: Assume the distance between A and B is d. How much distance does the person cover on her trip? How long does it take her to cover this distance?
4.8 m/s
A golf club exerts an average horizontal force of 1000 N on a 0.045-kg golf ball that is initially at rest on the tee. The club is in contact with the ball for 1.8 ms. What is the speed of the golf ball just as it leaves the tee?
40 m/s
Both ends of a piece of rope are pulled by two people in a tug-of-war. If each pulls with a 400-N force, the tension in the rope is
400 N.
You operate a 120 W light bulb for 1 hour. How much energy did you use? (1 W = 1 J/s)
432000 J
A rock is kicked horizontally at 10 m/s off a cliff. The rock strikes the ground 30 m from the cliff as shown in the figure. What is the approximate height of the cliff H?
45 m
Mercury has an unusually large surface tension γ = 0.465 N/m. Calculate the excess pressure inside a drop of mercury 4 mm in diameter.
465 Pa
A Carnot engine takes heat in from a reservoir at 400 K and discards heat to a reservoir at 300 K. If the engine does 12,000 J of work per cycle, how much heat does it take in per cycle?
48,000 J
An object rotates initially with a period of 1.0 s. It accelerates with constant angular acceleration for 10 s. Its final rotation period is 0.1 s.What was the magnitude of its angular acceleration?
5.65 rad/s2
A girl pushes a cart to the left with a 100-N force. At the same time a boy pushes it to the right with a 50-N force. The net force exerted on the cart is
50 N to the left.
How much heat transfer occurs from a system if its internal energy decreased by 150 J while it was doing 100.0 J of work?
50J
A CD spins at 5500 rpm (revolutions per minute). What is its angular speed in units of rad/s or s-1?
576
A 50 kg woman balances on one heel of a high-heel shoe. If the heel is circular with radius 0.5 cm, what pressure does she exert on the floor?
6.2 MPa
A boy throws a 0.1 kg ball from a height of 1.2 m to land on the roof of a building 8 m high. What is the potential energy of the ball on the roof relative to its starting point?
6.67 J
A 2 kg mass is at x = 0 m, y = 2 m, and a 3 kg mass is at x = 2 m, y = 0 m. The x- and y-coordinates, respectively, of the center of mass of this system are
6/5 m, 4/5 m
A 1200 kg car's speed changes from 0 to 20 m/s in 4 s. What is the average power of the car motor during this time period? Neglect the friction.
60,000 W
A car accelerates from 5.0 m/s to 21 m/s at a rate of 3.0 m/s 2 . How far does it travel while accelerating?
69 m
A train whistle is blown by the driver who hears the sound at 650 Hz. If the train is heading towards a station at 20.0 m/s, what will the whistle sound like to a waiting commuter? Take the speed of sound to be 340 m/s.
691 Hz
A block of mass m = 4.4 kg, moving on frictionless surface with a speed v i = 9.2 m/s makes a sudden perfectly elastic collision with a second block of mass M, as shown in the figure. The second block is originally at rest. Just after the collision, the 4.4-kg block recoils with a speed of v = 2.5 m/s. What is the mass M of the second block?
7.7 kg
A gas follows the process shown. What is the final-to-initial temperature ratio Tf /Ti ?
8
You are bored during the summertime when school is not in session and you decide to do an experiment where you compare the properties of water and air. If the density of air is 1.25 kg/m3 and the density of water is 1000 kg/m3, what volume of air weighs the same as 1 liter (10-3 m3) of water?
800 liters
The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of
81.
A sealed cubical container, 20 cm on a side, contains 3 times Avogadro's number of molecules at a temperature of 20 oC. What is the pressure in the container? (1 atm = 101 kPa)
9 atm
Two children pull a sled as shown. The sled moves with constant velocity v. Find the frictional force on the sled.
90.6 N
A particle is moving with constant speed along the circular path shown. Its velocity vector is shown at two different positions. What is the direction of the acceleration when the particle is at point X? (Recall the direction of centripetal acceleration and select the from the vectors A, B, C & D.)
A
Four sinusoidal sound waves propagate in the same region of our atmosphere. Rank the waves in order of their displacement amplitude, from largest to smallest. A. Intensity = 2.0*10^-5 W/m^2 = 100 Hz B. Intensity = 2.0*10^-5 W/m^2 = 200 Hz C. Intensity = 4.0*10^-5 W/m^2 = 200 Hz D. Intensity = 8.0*10^-5 W/m^2 = 800 Hz
A (LARGEST) C (LARGE) B (SMALL) D (SMALLEST)
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
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.
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
The vessels shown below all contain water to the same height. Rank them according to the pressure exerted by the water on the vessel bottoms, least to greatest.
All pressure are the same
The vessels shown below all contain water to the same height. Rank them according to the pressure exerted by the water on the vessel bottoms, least to greatest.
All pressures are the same.
Which sounds travel the fastest through air?
All sound travels at the same speed through air.
A block of ice (density 920 kg/m ), a block of concrete (density 2000 kg/m ), and a block of iron (density 7800 kg/m 3 ) are all submerged in the same fluid. All three blocks have the same volume. Which block experiences the greatest buoyant force?
All three experience the same buoyant force
Three trajectories labeled A, B, and C are shown below. For which trajectory is the vertical velocity component at launch the greatest?
All three trajectories have the same initial vertical velocity component at launch.
A ball is fired by a cannon from the top of a cliff as shown in the figure below. Which of the path would the cannonball most closely follow?
B
Rank the following temperatures from highest to lowest. A. 20.0°F, B. 20.0°C, C. 20.0 K, D. -80.0°F, E. -80.0°C
B. BADEC
Two pitchers are standing side by side, and simultaneously throw baseballs A and B. The balls follow the parabolic trajectories shown. Which of the following statements is true?
Ball B his the ground before ball A.
The interference of two sound waves of similar amplitude but slightly different frequencies produces a loud-soft-loud oscillation we call
Beats
1 kg of silver (c = 234 J/kg K) is heated to 100°C. It is then dropped into 1 kg of water (c = 4190 J/kg K) at 0°C in an insulated beaker. After a short while, the common temperature of the water and silver is
Between 0°C and 50°C
The picture below shows 5 blocks. The blocks have equal volumes but different masses. The blocks are placed in an aquarium tank filled with water and blocks 2 and 5 come to rest as shown in the figure. Which answer is correct?
Block 3 will come to rest in the same position as block 5.
A student throws a heavy red ball horizontally from a balcony of a tall building with an initial speed v i . At the same time, a second student drops a lighter blue ball from the balcony. Neglecting air resistance, which statement is true?
Both balls reach the ground at the same instant
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
Rank the following heat engines in order from highest to lowest thermal efficiency.
C. An engine that in one cycle does 800 J of work and rejects 5600 J of heat (HIGHEST) A. An engine that in one cycle absorbs 2500 J of heat and rejects 2250 J of heat B. An engine that in one cycle absorbs 50,000 J of heat and does 4000 J of work (LOWEST)
Car 1 starts from rest along a straight highway with constant acceleration a = 1 m/s2. Car 2 passes car 1 with constant velocity of 120 km/hr. Which car is acted on by a larger net force?
Car 1
Car 1 starts from rest along a straight highway with constant acceleration a = 1 m/s^2. Car 2 passes car 1 with constant velocity of 120 km/hr. Which car is acted on by a larger net force?
Car 1
Bob and Carl are riding on a merry-go-round. Bob is closer to the center of the merry-go-round. Who has the greater centripetal acceleration?
Carl
When a sample of 0ºC water is heated, it first
Contracts then expands.
An object moves with constant speed in the clockwise direction along the circular path shown below.At the point indicated by the black dot, in which direction is the angular velocity vector ω pointing?
D
A 100 Hz sound wave is traveling through the air. If we increase the frequency to 200 Hz, this will __________ the wavelength.
Decrease
The entropy of an isolated system
Either increases or remains constant.
You put an ice cube at 0°C inside a large metal box at 70°C. The ice melts and the entropy of the ice increases. Which statement is correct?
Entropy of the metal box decreases; total entropy increases.
Modeling a meter stick as a forearm, compare the force FB that the biceps has to exert to keep the forearm horizontal to the weight of the forearm FW = mg. Let d = 10 cm and the distance from where the biceps muscle attached to the center of mass be d' = 40 cm.
FB = 5 mg
Suppose you take off in a car with your physics book on top. If you are accelerating forward and the book rides with you, in what direction does friction act on the book?
Forwards
In soap box car races, the cars are boxes with wheels. They begin at rest at the top of a hill, and at the start of the race they all begin rolling down the hill. The soap box car that reaches the bottom of the hill first is the winner. You have entered a soap box car race where the rule is that all the wheels and cars must have equal mass. Since you have taken Physics, you know that it is worse to have wheels with spokes (where the mass is mostly on the rim) rather than solid wheels because
Given the same torque, the wheels with spokes have a higher rotational mass or moment of inertia and therefore will have a smaller angular acceleration.
A sphere, a hoop, and a cylinder, all with the same mass M and the same radius R, are rolling along, all with the same speed v. Which has the most total kinetic energy?
Hoop
Consider two masses, each of size 2m at the ends of a light rod of length L with the axis of rotation through the center of the rod. The rod is doubled in length and the masses are halved. Compare IA and IB.
IA < IB
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
Two cyclists who weigh the same and have identical bicycles ride up the same mountain, both starting at the same time. Joe rides straight up the mountain, and Bob rides up the longer road that has a lower grade. Joe gets to the top before Bob. Which statement is true?
Ignoring friction and wind resistance, the amount of work done by Joe is equal to the amount of work done by Bob, but the average power exerted by Joe is greater than that of Bob.
A steady force pushes in the piston of a well-insulated cylinder. In this process, the temperature of the gas
Increases
A cylinder of gas has a frictionless but tightly sealed piston of mass M. A small flame heats the cylinder, causing the piston to slowly move upward. For the gas inside the cylinder, what kind of process is this?
Isobaric
A sample of nitrogen gas is inside a sealed container. The container is slowly compressed, while the temperature is kept constant. This is a ........................process.
Isothermal
A child is riding a bike and skids to a stop. What happens to their kinetic energy?
It is converted into thermal energy.
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b to c is isothermal. What can you conclude about the net entropy change of the gas during the cycle?
It is zero
A copper pot at room temperature is filled with room-temperature water. Imagine a process whereby the water spontaneously freezes and the pot becomes hot. Why is such a process impossible?
It violates the second law of thermodynamics.
A car's speed changes from 20 mph to 60 mph. By what factor does its kinetic energychange?
It will increase by a factor of 9.
A clever physics student is able to sneak a scale on a popular ride at an amusement park. Before the ride begins to move, the scale reads 700 N for the student's weight. As the ride lifts, it initially accelerates upward at 3 m/s2. At the top, the riders are held in suspense before the gondola is allowed to free fall downward with acceleration equal to g. What should the scale read for the student's apparent weight during the lift and the fall?
Lift: 910N, Fall: 0 N
Two liquids, A and B, have equal masses and equal initial temperatures. Each is heated for the same length of time over identical burners. Afterward, liquid A is hotter than liquid B. Which has the larger specific heat?
Liquid B
A sample of gas is in a cylinder with a moveable piston. The force on the piston can be varied, altering the pressure and volume. A sample of gas is taken from an initial state to a final state following a curve on the pV diagram shown. The final temperature is
Lower than the initial temperature.
Consider two projectiles that can be shot upward by spring guns from ground level. Object A is made of solid aluminum and has a mass of 50 grams. Object B is made of cast iron and has a mass of 200 grams. Masses A and B are both shot straight upward at the same time. Mass A is shot with a speed of 2 m/s and mass B with a speed of 1 m/s. Which one hits the ground first?
Mass B
Consider the earth spinning from west to east on its axis. It is slowing down in its rotation due to friction with the air. Using the right hand rule, in what direction is the frictional torque?
N pole to S pole
An ice‐cube sits in a bath of water. The water, the ice and the surrounding air are all at 0 oC. Does heat enter the ice cube?
No
Is it possible to cool down a well insulated room on a hot summer day by leaving the refrigerator door open, and using the refrigerator as an air conditioner?
No
A point on a standing wave that is always stationary is a.............
Node
Two moving objects have masses m1 and m2, respectively. If m2 = 4m1, and both have the same kinetic energy, which has more momentum?
Object 2 with mass m2.
Which of the following statements about distance and/or displacement are TRUE? (1) Distance is a vector quantity and displacement is a scalar quantity.(2) If a person walks in a straight line and never changes direction, then the distance and the magnitude of the displacement are exactly the same. (3) The diagram below depicts the path of a person walking from position A to B back to C to and then to D. The distance traveled is 90 yds. (4) For the same diagram below, the displacement of the person walking from A to B to C to D is 50 yds.
Only statements 2 and 3 are true
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.
A DVD is rotating with an ever increasing speed. How do the angular velocity, angular acceleration, tangential velocity, and tangential acceleration compare at points P and Q?
Points P and Q have the same angular velocity and the same angular acceleration.
In a stationary homogeneous liquid near the surface of Earth, which of the following is true?
Pressure is the same at all points at the same height.
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. For process c a,
Q < 0, ∆U < 0
An ideal gas is taken around the cycle shown in this p-V diagram, from a to c to b and back to a. Process c b is adiabatic. For process c to b,
Q = 0, W < 0, ∆U > 0
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. For this complete cycle,
Q > 0, W > 0, ∆U = 0
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. For process b to c,
Q > 0, ∆U = 0
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. For process a to b,
Q > 0, ∆U > 0
Which type of heat transfer can happen efficiently through empty space?
Radiation
In the constellation Orion, you can easily observe the difference between the reddish looking star Betelgeuse and the bluish looking star Rigel. Which of the two has the hotter surface temperature?
Rigel
A firecracker explodes in midair and breaks up into many fragments. Which of the following statements are true regarding conditions immediately before and immediately after the explosion? I. The total momentum of the fragments is equal to the original momentum of the firecracker. II. The total kinetic energy of the fragments is equal to the original kinetic energy of the firecracker.
Statement I only
A kid is swinging on a swing with a period T. A second kid climbs on with the first, doubling the weight on the swing. The period of the swing is now
T
A wave on a string is moving to the right. This graph of y(x, t) versus coordinate x for a specific time t shows the shape of part of the string at that time. At this time, what is the acceleration of a particle of the string at x = a?
The acceleration is downward.
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.
When the temperature of an ideal gas is increased, which of the following also increases?
The average kinetic energy of the gas atoms
Suppose Larissa throws a ball up in the air and it comes back down to the same place she threw it from. Ignore the times when the ball is in contact with her hand, and ignore air resistance.
The ball has minimum kinetic and maximum potential energy at maximum height.
A block and a rod are joined together. Each object is of uniform density. The center of mass of the combined object is at the position shown by the "X."Which has the greater mass, the block or the rod?
The block has the greater mass.
A bullet is fired horizontally from a rifle on the Moon (no air, g = 1.6 m/s2) with initial speed v0. Assuming a level and endless ground, which statement is false?
The flight time increases as v0 increases.
An ideal, non-compressible fluid is used in the system of pipes shown below. The cross sectional area of pipe 1 is 4 m2, that of pipe 2 is 3 m2, and that of pipe 3 is 2 m2. The fluid enters pipe 1 at 2 m/s, and leaves pipe 2 at 3 m/s. What is the speed of the fluid in pipe 3 and in which direction does it flow?
The fluid leaves pipe 3 (downward) with speed 0.5 m/s.
Consider a marble rolling around in a bowl sitting on a table on Earth. Neglect friction. Which of the following statements is true?
The gravitational potential energy of the marble depends on the choice of the reference position for zero potential energy.
A chair has a wooden seat but metal legs. The chair legs feel colder to the touch than does the seat. Why is this?
The metal has a higher thermal conductivity than the wood.
A chair has a wooden seat but metal legs. The chair legs feel colder to the touch than does the seat. Why?
The metal has a higher thermal conductivity than the wood.
In an inertial frame, an object cannot remain at rest unless which of the following holds?
The net force acting on it is zero.
A box is at rest on a flat table. Which of the following is true?
The normal force and the gravitational force are equal in magnitude and opposite in direction
An object moves in a circle with constant speed.
The object is accelerating. It is acted on by a radial force, pointing towards the center of the circle.
If the net work done on an object is negative, which of the following statements must be true?
The object loses kinetic energy.
A force of 20 N in the positive x‐direction accelerates an object giving it a = 2 m/s2. When the object is moving with velocity v = 10 m/s, an additional force of 10 N in the negative x‐direction is applied. Which statement is true?
The object now accelerates with acceleration a = 1 m/s2 in the positive x‐direction.
At a compression in a sound wave,
The particle displacement is zero.
A train sounding its horn is approaching an observer.
The pitch of the horn's sound relative to its normal pitch is higher.
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.
Which statement about these two thermodynamic processes is correct?
The upper one is reversible and the lower one is irreversible.
A wave on a string is moving to the right. This graph of y(x, t) versus coordinate x for a specific time t shows the shape of part of the string at that time. At this time, what is the velocity of a particle of the string at x = b?
The velocity is upward.
A wave on a string is moving to the right. This graph of y(x, t) versus coordinate x for a specific time t shows the shape of part of the string at that time. At this time, what is the velocity of a particle of the string at x = a?
The velocity is zero.
You immerse a 1-kg block of iron in 1 kg of water in an insulated chamber, add 100 J of heat, and allow the iron and water to equilibrate to the same temperature. Which has absorbed more heat, the iron or the water?
The water absorbs more heat.
You throw a ball straight up. Compare the sign of the work done by the force of gravity while the ball goes up with the sign of the work done by gravity while it goes down.
The work done by the force of gravity is negative on the way up and positive on the way down.
Which of the following assumptions is not made in the derivation of Bernoulli's equation?
There is negligible gravity.
Why do elastic balls bounce so well?
They store energy through compression, like a spring.
If only conservative forces act on a system, the total mechanical energy of the system remains constant.
True
It is possible to heat to flow across vacuum
True
The graph shows the net force acting on an astronaut during a rocket launch into a stable orbit. During which time interval was the acceleration of the rocket the greatest?
U-V
Which has the higher specific heat, water or land?
Water
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.
It is possible for heat to flow across vacuum.
Yes
Suppose you are on a cart, initially at rest on a frictionless, horizontal track. You throw a series of identical balls against a wall that is rigidly mounted to the cart. If the balls are thrown at a steady rate and bounce straight back, is the cart put into motion?
Yes, it starts to move to the left and steadily gains speed.
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.
On a day when there is no wind, you are at rest and a source of sound waves is moving toward you. Compared to what you would hear if the source were not moving, the sound that you hear has
a higher frequency and a shorter wavelength.
On a day when there is no wind, you are moving toward a stationary source of sound waves. Compared to what you would hear if you were not moving, the sound that you hear has
a higher frequency and the same wavelength.
Work, as defined in physics is
a scalar quantity, a positive or negative number with units.
As a sound source moving with constant velocity approaches and then moves past a stationary observer, the observer will hear
a sudden drop in pitch
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. Rank the following processes in order of the value of the internal energy ∆U of the ideal gas in the process, from most positive to most negative.
a to b (MOST POSITIVE) b to c c to a (MOST NEGATIVE)
The shape of a droplet of liquid on a surface is due to a combination of
adhesion and cohesion.
The Bernoulli effect is responsible for the lift force on an airplane wing. Wings must therefore be designed so as to insure that
air molecules move more rapidly past the upper surface of the wing than past the lower surface.
Which of the following wave functions describe(s) a wave that moves in the -x-direction?
all of A, B, and C
The illustration shows a thermometer that uses a column of liquid (usually mercury or ethanol) to measure air temperature. In thermal equilibrium, this thermometer measures the temperature of
all of A, B, and C.
Which of the following wave functions describe a wave that moves in the ‐x‐direction? 1. y(x,t) = A sin (-kx - ωt) 2. y(x,t) = A sin (kx + ωt) 3. y(x,t) = A cos (kx + ωt)
all of them
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
The left tip of a wind turbine blade accelerates upward, as you view it. By the right-hand rule, the torque on the wind turbine is pointing
away from you
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. Which of the processes in this cycle could be reversible?
b to c
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. Rank the following processes in order of the value of the work W done by the ideal gas in the process, from most positive to most negative.
b to c (MOST POSITIVE) a to b c to a (MOST NEGATIVE)
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b c is isothermal. Rank the following processes in order of the value of the heat Q into the ideal gas in the process, from most positive to most negative.
b to c (MOST POSITIVE) a to b c to a (MOST NEGATIVE)
A bubble of air released from the bottom of a lake
becomes larger as it rises.
This p-V diagram shows two ways to take a system from state a (at lower left) to state c (at upper right): • via state b (at upper left), or • via state d (at lower right) For which path is W > 0?
both path abc and path adc
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
An ideal gas is taken around the cycle shown in this p-V diagram, from a to c to b and back to a. Process c b is adiabatic. Which of the processes in this cycle could be reversible?
c to b
Living cells constitute a low entropy state of matter. Living cells
can exist because they help increase the entropy of the rest of the universe.
Increasing the pressure amplitude of a sound wave by a factor of 4 (while leaving the frequency unchanged)
causes the intensity to increase by a factor of 16.
The first law of thermodynamics is a re-statement of the law of
conservation of energy.
When you first step out of a swimming pool on a warm day, you feel cool. This is due primarily to
convection
After a ball is thrown upward and is in the air, what will its speed do?
decrease and then increase
A grandfather clock is running slow. The period of its pendulum is too long. To shorten the period and make the clock run faster, you should.
decrease the length of the pendulum.
A skier skis in a straight line down a hill gradually picking up speed as he goes. Which of the following could plausibly be an external force diagram for the skier during this motion? Assume air resistance is negligible.
diagram d
A boat is floating in a lake. Since it is floating the buoyant force acting on the boat must be
equal to its weight.
A rock is thrown from the roof of a tall building.While it is falling towards the ground, the force of gravity acting on it is
equal to its weight.
In an isothermal expansion of an ideal gas, the amount of heat that flows into the gas
equals the amount of work done by the gas.
When a hot cup is filled with cold water, the direction of heat flow is
from the cup to the water.
A sample of a low-density gas is initially at room temperature and has pressure P0. The gas is warmed at constant volume until the pressure is 2P0. Compared to the initial Celsius temperature of the gas, the final Celsius temperature is
greater by a factor of more than 2.
A sample of a low-density gas is initially at room temperature and has pressure p 0 . The gas is warmed at constant volume until the pressure is 2p 0 . Compared to the initial Celsius temperature of the gas, the final Celsius temperature is
greater by a factor of more than 2.
An ideal gas begins in a thermodynamic state a. When the temperature of the gas is raised from T 1 to a higher temperature T 2 at a constant volume, a positive amount of heat Q 12 flows into the gas. If the same gas begins in state a and has its temperature raised from T 1 to T 2 at a constant pressure, the amount of heat that flows into the gas is
greater than Q12
Suppose you have two containers with liquid in them. One has a density of 760 kg/m3and the other has a density of 910 kg /m3. If an object floats in one container and sinks in the other, the density of the object
has a value between 760 kg/m3 and 910 kg/m3.
Increasing the frequency of a sound wave by a factor of 4 (while leaving the pressure amplitude unchanged)
has no effect on the wave intensity.
A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed v0. The constant horizontal force supplied by the woman
has the same magnitude as the total force which resists the motion of the box.
During a football game the ball is kicked and it travels across the field. If the ball is kicked away from its center of mass it will
have translational and rotational motion.
A heat engine extracts usable work by permitting
heat to flow from a hotter object to a colder object.
A man, with his arms at his sides, is spinning on a light frictionless turntable. When he extends his arms
his angular momentum remains the same.
Flowing honey is less likely to become turbulent than flowing water because
honey's large viscosity favors laminar flow
A solid object has a hole in it. Which of these illustrations more correctly shows how the size of the object and the hole change as the temperature increases?
illustration #1
You paddle in a Kayak across a calm mountain lake. Each time you pull the paddle backward through the water, from the front of the boat to its rear, the water exerts a force on the paddle that is
in the forward direction, towards the front of the boat.
If a viscous fluid flows steadily in a pipe, the fluid speed
is least near the pipe wall but increases toward the center.
An ideal gas is taken around the cycle shown in this p-V diagram, from a to b to c and back to a. Process b to c is isothermal. What can you conclude about the net entropy change of the gas and its environment during the cycle?
it is positive
A car's speed changes from 20 mph to 60 mph. By what factor does its kinetic energy change?
it will increase by a factor of 9
At constant pressure, the volume of a gas sample is directly proportional to
its absolute temperature.
Newton's second law of motion says that the mass of an object times its acceleration is equal to the net force on the object. Which of the following gives the correct units for force?
kg*m/s 2
The SI units for viscosity are
kg/(m-s)
When an ideal gas is allowed to expand isothermally from volume V1 to a larger volume V2 , the gas does an amount of work equal to W12. If the same ideal gas is allowed to expand adiabatically from volume V1 to a larger volume V2 , the gas does an amount of work that is
less than W12
Water pours gently from an open hose because it
lost energy throughout its trip to the hose end.
The density of freshwater is 1 g/cm and the density of seawater is 1.03 g/cm . A ship will float
lower in freshwater than in sea water.
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.
In the absence of air resistance, a ball of mass m is tossed upward to reach a height of 20 m. At the 15 m position, 3/4 of the way up, the net force on the ball is
mg (mass times gravity)
The quantities remain constant in an inelastic collision are
momentum, but neither kinetic energy nor temperature.
A system can be taken from state a to state b along any of the three paths shown in the p-V diagram. If state b has greater internal energy than state a, along which path is there a net flow of heat out of the system?
none of paths 1, 2, or 3
Two cylinders, A and B, contain the same type of gas at the same temperature. Cylinder A has twice the volume as cylinder B and contains half as many molecules as cylinder B. Which is true?
pA = (pB)/4
A system can be taken from state a to state b along any of the three paths shown in the p-V diagram. If state b has greater internal energy than state a, along which path is the absolute value |Q| of the heat transfer the greatest?
path 1
A wave on a string is moving to the right. This graph of y(x, t) versus coordinate x for a specific time t shows the shape of part of the string at that time. At this time, the velocity of a particle on the string is upward at
point 2 and point 6 only.
Rockets receive their forward propulsion through
pushing against the exhaust.
People fighting forest fires carry emergency tents that have shiny aluminum outer surfaces. If there is trouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tent helps because
radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation.
A pitcher contains 0.50 kg of liquid water at 0°C 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.
A simple pendulum consists of a point mass suspended by a massless, unstretchable string. 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.
When stringing telephone lines between poles in the summer, it is advisable to allow the lines to
sag.
A skater who is spinning and throws her arms out slows down because
she makes her rotational mass or moment of inertia bigger.
Two cars move towards each other on a frictionless road as shown in the sketch below. The two cars collide and immediately come to a standstill. During the collision, the total momentum of the two vehicles will
stay constant.
This is an x-t graph for an object in simple harmonic motion. At which of the following times does the object have the most negative acceleration a x ?
t = T
Two objects in thermal equilibrium have the same
temperature.
One kilogram of iron (density ~7.8 gm/cm3) and 1 kilogram of aluminum (density ~2.7 gm/cm3) are dropped into a pool. Which is acted on by the largest buoyant force?
the aluminum
Your hands push on a heavy box to slide it across the floor with constant velocity. The other force of the action/reaction pair is
the box pushing backward against your hands.
When you sit facing a campfire outdoors, your face feels quite warm because
the campfire is radiating heat towards your skin.
It is correct to say that impulse is equal to
the change in momentum.
As I apply the brakes in my car, books on the passenger seat suddenly fly forward. That is most likely because
the decelerating car is not an inertial reference frame.
No work is done by gravity on a bowling ball that rolls along a bowling alley because
the force of gravity is perpendicular to the balls velocity.
After clearing the bar on a high jump, you land softly on a giant mattress. Landing on a mattress is more comfortable than landing on a sand heap of equal size because
the force the mattress exerts on you to stop your descend is much less than the force the sand heap would exert on you.
While an object is in projectile motion (with upward being positive) with no air resistance,
the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to -g.
The longer the wavelength of a sound wave
the lower is its pitch.
It is possible for two objects of equal mass to have different moments of inertia about the same axis because
the moment of inertia depends on the total mass and the mass distribution.
Consider a car at rest. We can conclude that the downward gravitational force Earth exerts on the car and the upward contact force the surface of Earth exerts on the car are equal in magnitude and opposite in direction because
the net force on the car at rest is zero.
If you dangle two pieces of paper vertically a few inches apart and blow air between them
the papers will move together because the increased velocity reduces the pressure between the papers.
The maintenance of the life cycle depends on
the presence of a source and a sink of energy.
A beaker is filled with water to the rim. Gently you place a toy duck in the beaker and some of the water spills out. The duck floats. The weight of the beaker with the duck floating in it is
the same as its weight before adding the duck.
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.
Compared to a gear tooth on the rear sprocket (on the left, of small radius) of a bicycle, a gear tooth on the front sprocket (on the right, of large radius) has
the same linear speed and a slower angular speed.
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.
You wish to increase the temperature of a 1.00-kg block of a certain solid substance from 20°C to 25°C. (The block remains solid as its temperature increases.) To calculate the amount of heat required to do this, you need to know
the specific heat of the substance.
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.
An elevator is being lifted up an elevator shaft at a constant speed by a steel cable as shown in the figure above. All frictional effects are negligible. In this situation, forces on the elevator are such that
the upward force by the cable is equal to the downward force of gravity.
During a brown-out, the electric power company drops the voltage of the power line and the incandescent light bulbs in your house become dimmer. When this happens, the filaments in the bulbs operate at a lower than normal temperature, so
their color is somewhat redder than normal.
How many nodes and antinodes are shown in the standing wave below?
three nodes and two antinodes
You are riding an amusement park ride where you are strapped to the inside of a giant metal wheel. During some time interval the wheel is horizontal and rotating uniformly and rapidly. During this time interval your acceleration is
towards the center of the wheel.
If you double the wavelength of a wave on a string, what happens to the wave speed v and the wave frequency f ?
v is unchanged and f is halved.
Sound does not pass through
vacuum
A traffic light of weight w hangs from two lightweight cables as shown. Each cable hangs at a 45 angle from the vertical. What is the tension in each cable?
w/ √2
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.
If a car is traveling eastward and slowing down, what is the direction of the force on the car that causes it to slow down?
westward
The force on a damped oscillator is F x = -kx - bv x . During its motion, the oscillator loses mechanical energy most rapidly
when it is passing through the equilibrium position.
The angular momentum of a system remains constant
when no torque acts on the system.
A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed v0. If the woman doubles the constant horizontal force that she exerts on the box, and the force resisting the motion of the box does not change, the box then moves
with constantly increasing speed.
Is it possible to have motion in the absence of a net force?
yes
If you were to move into outer space far from any stars or planets,
your weight would change, but your mass would not change.
Three blocks are connected as shown. The ropes and pulleys are of negligible mass. When released, block C moves downward, block B moves up the ramp, and block A moves to the right. After each block has moved a distance d, the force of gravity has done
zero work on A, negative work on B , and positive work on C.
You hear the sound of the ring of a distant cannon 5 seconds after seeing the flash. How far are you from the cannon?
~1700 m
