AP Physics 1
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Work and Energy Practice Multiple Choice Solutions
1) Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the
following statements is correct?
A) Both do positive work, but person X does four times the work of person Y.
B) Both do positive work, but person X does twice the work of person Y.
C) Both do the same amount of positive work.
D) Both do zero work.
E) Both do positive work, but person X does one-half the work of person Y.
Answer: D
Var: 1
2) Two men, Joel and Jerry, push against a car that has stalled, trying unsuccessfully to get it
moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work
they do on the car.
A) Joel does 75% more work than Jerry.
B) Joel does 50% more work than Jerry.
C) Jerry does 50% more work than Joel.
D) Joel does 25% more work than Jerry.
E) Neither of them does any work.
Answer: E
Var: 1
3) If the force on an object is in the negative direction, the work it does on the object must be
A) negative.
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B) positive.
C) The work could be either positive or negative, depending on the direction the object moves.
Answer: C
Var: 1
4) A 35-N bucket of water is lifted vertically 3.0 m and then returned to its original position.
How much work did gravity do on the bucket during this process?
A) 180 J
B) 90 J
C) 45 J
D) 0 J
E) 900 J
Answer: D
Var: 1
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5) You throw a baseball straight up. Compare the sign of the work done by gravity while the ball
goes up with the sign of the work done by gravity while it goes down.
A) The work is positive on the way up and positive on the way down.
B) The work is positive on the way up and negative on the way down.
C) The work is negative on the way up and positive on the way down.
D) The work is negative on the way up and on the way down because gravity is always
downward.
Answer: C
Var: 1
6) Which one has larger kinetic energy: a 500-kg object moving at 40 m/s or a 1000-kg object
moving at 20 m/s?
A) The 500-kg object
B) The 1000-kg object
C) Both have the same kinetic energy.
Answer: A
Var: 1
7) A truck has four times the mass of a car and is moving with twice the speed of the car. If Kt
and Kc refer to the kinetic energies of truck and car respectively, it is correct to say that
A) Kt = 16Kc.
B) Kt = 4Kc.
C) Kt = 2Kc.
D) Kt = Kc.
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E) Kt = Kc.
Answer: A
Var: 1
8) Three cars (car F, car G, and car H) are moving with the same speed and slam on their brakes.
The most massive car is car F, and the least massive is car H. If the tires of all three cars have
identical coefficients of kinetic friction with the road surface, which car travels the longest
distance to skid to a stop?
A) They all travel the same distance in stopping.
B) Car F
C) Car G
D) Car H
Answer: A
Var: 1
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9) Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes.
The most massive car is car L, and the least massive is car N. If the tires of all three cars have
identical coefficients of kinetic friction with the road surface, for which car is the amount of
work done by friction in stopping it the greatest?
A) The amount of work done by friction is the same for all cars.
B) Car L
C) Car M
D) Car N
Answer: B
Var: 1
10) A 4.0 kg object is moving with speed 2.0 m/s. A 1.0 kg object is moving with speed 4.0 m/s.
Both objects encounter the same constant braking force, and are brought to rest. Which object
travels the greater distance before stopping?
A) the 4.0 kg object
B) the 1.0 kg object
C) Both objects travel the same distance.
D) It cannot be determined from the information given.
Answer: C
Var: 1
11) You slam on the brakes of your car in a panic, and skid a certain distance on a straight level
road. If you had been traveling twice as fast, what distance would the car have skidded, under
the same conditions?
A) It would have skidded 4 times farther.
B) It would have skidded twice as far.
C) It would have skidded 1.4 times farther.
D) It would have skidded one half as far.
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E) It is impossible to tell from the information given.
Answer: A
Var: 1
12) Which requires more work, increasing a car's speed from 0 mph to 30 mph or from 50 mph
to 60 mph?
A) 0 mph to 30 mph
B) 50 mph to 60 mph
C) It is the same in both cases.
Answer: B
Var: 1
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13) A stone is held at a height h above the ground. A second stone with four times the mass of
the first one is held at the same height. The gravitational potential energy of the second stone
compared to that of the first stone is
A) one-fourth as much.
B) one-half as much.
C) twice as much.
D) four times as much.
E) the same.
Answer: D
Var: 1
14) You and your friend, who weighs the same as you, want to go to the top of the Eiffel Tower.
Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking
longer to do so. Compare the gravitational potential energy of you and your friend, after you both
reach the top.
A) It is impossible to tell, since the times you both took are unknown.
B) It is impossible to tell, since the distances you both traveled are unknown.
C) Your friend's gravitational potential energy is greater than yours, because he got to the top
faster.
D) Both of you have the same amount of gravitational potential energy at the top.
E) Your gravitational potential energy is greater than that of your friend, because you traveled a
greater distance in getting to the top.
Answer: D
Var: 1
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15) The graphs shown show the magnitude F of the force exerted by a spring as a function of the
distance x the spring has been stretched. For which one of the graphs does the spring obey
Hooke's law?
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A) Graph a
B) Graph b
C) Graph c
D) Graph d
E) Graph e
Answer: B
Var: 1
16) A heavy dart and a light dart are launched horizontally on a frictionless table by identical
ideal springs. Both springs were initially compressed by the same amount. Which of the
following statements about these darts are correct? (There could be more than one correct
choice.)
A) The darts both have the same kinetic energy just as they move free of the spring.
B) The lighter dart leaves the spring moving faster than the heavy dart.
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C) The heavy dart had more initial elastic potential energy than the light dart.
D) Both darts move free of the spring with the same speed.
E) Both darts had the same initial elastic potential energy.
Answer: A, B, E
Var: 1
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17) When you throw a pebble straight up with initial speed V, it reaches a maximum height H
with no air resistance. At what speed should you throw it up vertically so it will go twice as high?
A) 16V
B) 8V
C) 4V
D) 2V
E)
V
Answer: E
Var: 1
18) When you drop a pebble from height H, it reaches the ground with speed V if there is no air
resistance. From what height should you drop it so it will reach the ground with twice speed?
A)
H
B) 2H
C) 4H
D) 8H
E) 16H
Answer: C
Var: 1
19) When you drop a pebble from height H, it reaches the ground with kinetic energy K if there
is no air resistance. From what height should you drop it so it will reach the ground with twice as
much kinetic energy?
A)
H
B) 2H
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C) 4H
D) 8H
E) 16H
Answer: B
Var: 1
20) Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building.
If there is no air resistance, when they hit the ground
A) both will have the same kinetic energy.
B) the heavier one will have twice the kinetic energy of the lighter one.
C) the heavier one will have four times the kinetic energy of the lighter one.
D) the heavier one will have half the kinetic energy of the lighter one.
E) the heavier one will have one-fourth the kinetic energy of the lighter one.
Answer: B
Var: 1
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21) Swimmers at a water park have a choice of two frictionless water slides, as shown in the
figure. Although both slides drop over the same height h, slide 1 is straight while slide 2 is
curved, dropping quickly at first and then leveling out. How does the speed v1 of a swimmer
reaching the bottom of slide 1 compare with v2, the speed of a swimmer reaching the end of slide
2?
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A) v1 > v2
B) v1 < v2
C) v1 = v2
D) The heavier swimmer will have a greater speed than the lighter swimmer, no matter which
slide he uses.
E) No simple relationship exists between v1 and v2.
Answer: C
Var: 1
22) Two frisky otters slide down frictionless hillsides of the same height but different slopes. The
slope of the hill of otter 1 is 30°, while the slope of the hill of otter 2 is 60°. If both start from
rest, which otter is moving faster when she reaches the bottom of her hill?
A) Otter 1 is moving faster.
B) Otter 2 is moving faster.
C) The heavier otter is moving faster, no matter which hill she used.
D) Both otters have the same speed at the bottom.
E) The otter that took the shorter time is moving faster.
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Answer: D
Var: 1
23) A lightweight object and a very heavy object are sliding with equal speeds along a level
frictionless surface. They both slide up the same frictionless hill with no air resistance. Which
object rises to a greater height?
A) The heavy object, because it has greater initial kinetic energy.
B) The light object, because gravity slows it down less.
C) The lightweight object, because the force of gravity on it is less.
D) The heavy object, because it has more mass to carry it up the hill.
E) They both slide to exactly the same height.
Answer: E
Var: 1
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24) A person stands on the edge of a cliff. She throws three identical rocks with the same speed.
Rock X is thrown vertically upward, rock Y is thrown horizontally, and rock Z is thrown
vertically downward. If the ground at the base of the cliff is level, which rock hits the ground
with the greatest speed if there is no air resistance?
A) Rock X
B) Rock Y
C) Rock Z
D) They all hit the ground with the same speed.
Answer: D
Var: 1
25) Joe and Bill throw identical balls vertically upward. Joe throws his ball with an initial speed
twice as high as Bill. If there is no air resistance, the maximum height of Joe's ball will be
A) four times that of Bill's ball.
B) two times that of Bill's ball.
C) equal to that of Bill's ball.
D) eight times that of Bill's ball.
E) roughly 1.4 times that of Bill's ball.
Answer: A
Var: 1
26) A stone can slide down one of four different frictionless ramps, as shown in the figure. For
which ramp will the speed of the ball be the greatest at the bottom?
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A) Ramp X
B) Ramp Y
C) Ramp Z
D) The speed of the ball will be the same for all ramps.
Answer: D
Var: 1
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27) A girl throws a stone from a bridge. Consider the following ways she might throw the stone.
The speed of the stone as it leaves her hand is the same in each case.
Case A: Thrown straight up.
Case B: Thrown straight down.
Case C: Thrown out at an angle of 45° above horizontal.
Case D: Thrown straight out horizontally.
In which case will the speed of the stone be greatest when it hits the water below if there is no
significant air resistance?
A) Case A
B) Case B
C) Case C
D) Case D
E) The speed will be the same in all cases.
Answer: E
Var: 1
28) A heavy frog and a light frog jump straight up into the air. They push off in such away that
they both have the same kinetic energy just as they leave the ground. Air resistance is negligible.
Which of the following statements about these frogs are correct? (There could be more than one
correct choice.)
A) Just as they leave the ground, the heavier frog is moving faster than the lighter frog.
B) Just as they leave the ground, the lighter frog is moving faster than the heavier frog.
C) They both leave the ground with the same speed.
D) The lighter frog goes higher than the heavier frog.
E) The heavier frog goes higher than the lighter frog.
F) Both frogs reach the same maximum height.
Answer: B, F
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Var: 1
29) Two identical grasshoppers jump into the air with the same initial speed and experience no
air resistance. Grasshopper A goes straight up, but grasshopper B goes up at a 66° angle above
the horizontal. Which of the following statements about these grasshoppers are correct? (There
could be more than one correct choice.)
A) At their highest point, both of them have the same amount of gravitational potential energy.
B) At their highest point, both of them have the same amount of kinetic energy.
C) At their highest point, both of them have the same amount of mechanical energy.
D) At their highest point, grasshopper B is moving faster than grasshopper A.
E) At their highest point, grasshopper A has more gravitational potential energy than grasshopper
B.
Answer: C, D, E
Var: 1
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30) A heavy rock and a light rock are dropped from the same height and experience no
significant air resistance as they fall. Which of the following statements about these rocks are
correct? (There could be more than one correct choice.)
A) Both rocks have the same kinetic energy when they reach the ground.
B) Both rocks have the same speed when they reach the ground.
C) The heavier rock reaches the ground before the lighter rock.
D) Just as they were released, both rocks had the same amount of gravitational potential energy.
E) When they reach the ground, the heavier rock has more kinetic energy than the lighter rock.
Answer: B, E
Var: 1
31) A heavy stone and a light stone are released from rest in such away that they both have the
same amount of gravitational potential energy just as they are released. Air resistance is
negligibly small. Which of the following statements about these stones are correct? (There could
be more than one correct choice.)
A) The initial height of the light stone is greater than the initial height of the heavy stone.
B) The stones must have been released from the same height.
C) The stones both have the same speed just as they reach the ground.
D) Just as it reaches the ground, the light stone is traveling faster than the heavy stone.
E) The stones both have the same kinetic energy just as they reach the ground.
Answer: A, D, E
Var: 1
32) A 1-kg ball is released from a height of 6 m, and a 2-kg ball is released from a height of 3 m.
Air resistance is negligible as they fall. Which of the following statements about these balls are
correct? (There could be more than one correct choice.)
A) As they reach the ground, the 1-kg ball will have more kinetic energy than the 2-kg ball
because it was dropped from a greater height.
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B) As they reach the ground, the 1-kg ball will be moving faster than the 2-kg ball.
C) Both balls will reach the ground with the same speed.
D) Both balls will reach the ground with the same kinetic energy.
E) Both balls will take the same time to reach the ground.
Answer: B, D
Var: 1
33) A heavy dart and a light dart are launched vertically by identical ideal springs. Both springs
were initially compressed by the same amount. There is no significant air resistance. Which of
the following statements about these darts are correct? (There could be more than one correct
choice.)
A) The heavy dart goes higher than the light dart.
B) The light dart goes higher than the heavy dart.
C) Both darts reach the same maximum height.
D) At the maximum height, both darts have the same gravitational potential energy.
E) Both darts began moving upward with the same initial speed.
Answer: B, D
Var: 1
Answer: E
Var: 1
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