Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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1.
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A ball with
a momentum of 4.0 kg·m/s hits a wall and bounces straight back without losing any kinetic energy. What is
the change in the ball’s momentum? a. | –4.0 kg·m/s | c. | 8.0 kg·m/s | b. | 0.0 kg·m/s | d. | –8.0
kg·m/s | | | | |
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2.
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Which of the
following statements properly relates the variables in the equation FDt = Dp? a. | A large constant force changes an object’s momentum at various
time intervals. | b. | A large constant force does not necessarily cause a change in an
object’s momentum. | c. | A large constant force acting over a long time interval causes a large
change in momentum. | d. | A large constant force changes an object’s momentum over a long
time interval. | | |
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3.
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A 90 kg
halfback runs north and is tackled by a 120 kg opponent running south at 4 m/s. The collision is
perfectly inelastic. Just after the tackle, both players move at a velocity of 2 m/s north. Calculate
the velocity of the 90 kg player just before the tackle. a. | 4 m/s
south | c. | 10 m/s
north | b. | 12 m/s north | d. | 3 m/s south | | | | |
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4.
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A large
moving ball collides with a small stationary ball. The momentum a. | of the large ball
increases, and the momentum of the small ball decreases. | b. | of the large ball
decreases, and the momentum of the small ball increases. | c. | of the small ball
decreases, and the momentum of the large ball increases. | d. | does not change for
either ball. | | |
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5.
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Two skaters,
each with a mass of 50 kg, are stationary on a frictionless ice pond. One skater throws a 0.2 kg ball
at 5 m/s to the other skater, who catches it. What are the velocities of the skaters when the ball is
caught? a. | 0.02 m/s moving toward
each other | c. | 0.04 m/s moving
apart | b. | 0.04 m/s moving toward each other | d. | 0.02 m/s moving apart | | | | |
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6.
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The law of
conservation of momentum states that a. | the total momentum of all objects interacting with one another remains
constant regardless of the nature of the forces between the objects. | b. | the total initial
momentum of all objects interacting with one another does not equal the total final
momentum. | c. | the total initial momentum of all objects interacting with one another
usually equals the total final momentum. | d. | the total momentum of all objects interacting with one another is
zero. | | |
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7.
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Two balls of
dough collide and stick together. Identify the type of collision. a. | perfectly
inelastic | c. | inelastic | b. | elastic | d. | perfectly elastic | | | | |
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8.
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A force is
applied to stop a moving shopping cart. Increasing the time interval over which the force is
applied a. | requires a greater
force. | c. | requires the same
force. | b. | requires a smaller force. | d. | has no effect on the force needed. | | | | |
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9.
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A bullet
with a mass of 5.00 ´ 10–3 kg is loaded into a gun. The loaded gun has a mass of 0.52 kg.
The bullet is fired, causing the empty gun to recoil at a speed of 2.1 m/s. What is the speed of the
bullet? a. | 120
m/s | c. | 360
m/s | b. | 48
m/s | d. | 220
m/s | | | | |
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10.
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A 1.5
´ 103 kg
truck moving at 15 m/s strikes a 7.5 ´ 102 kg automobile stopped at a traffic light. The vehicles hook bumpers
and skid together at 10.0 m/s. What is the decrease in kinetic energy? a. | 1.1 ´ 105
J | c. | 6.0 ´ 104
J | b. | 1.7 ´ 105 J | d. | 1.2 ´ 104 J | | | | |
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11.
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Which of the
following has the greatest momentum? a. | car with a mass of 1210 kg moving at a velocity of 51
m/s | b. | truck with a mass of
6120 kg moving at a velocity of 10 m/s | c. | truck with a mass of 2250 kg moving at a velocity of 25
m/s | d. | car with a mass of 1540
kg moving at a velocity of 38 m/s | | |
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12.
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An infant
throws 5 g of applesauce at a velocity of 0.2 m/s. All of the applesauce collides with a nearby wall
and sticks. What is the decrease in kinetic energy of the applesauce? a. | 1 ´ 10–4
J | c. | 0.5 ´ 10–4
J | b. | 1 ´ 10–3
J | d. | 2 ´ 10–4
J | | | | |
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13.
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A clay ball
with a mass of 0.35 kg strikes another 0.35 kg clay ball at rest, and the two balls stick together.
The final velocity of the balls is 2.1 m/s north. What was the first ball’s initial
velocity? a. | 4.2 m/s to the
south | c. | 2.1 m/s to the
north | b. | 2.1 m/s to the south | d. | 4.2 m/s to the north | | | | |
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14.
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A diver with
a mass of 80.0 kg jumps from a dock into a 130.0 kg boat at rest on the west side of the dock. If the
velocity of the diver in the air is 4.10 m/s to the west, what is the final velocity of the diver
after landing in the boat? a. | 2.52 m/s to the east | c. | 1.56 m/s to the west | b. | 2.52 m/s to the
west | d. | 1.56 m/s to the
east | | | | |
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15.
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A softball
with a mass of 0.11 kg moves at a speed of 12 m/s. Then the ball is hit by a bat and rebounds in the
opposite direction at a speed of 15 m/s. What is the change in momentum of the ball? a. | –0.33
kg·m/s | c. | –3.0
kg·m/s | b. | –1.6 kg·m/s | d. | –1.3 kg·m/s | | | | |
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16.
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Two carts
with masses of 1.5 kg and 0.7 kg, respectively, are held together by a compressed spring. When
released, the 1.5 kg cart moves to the left with a velocity of 7 m/s. What is the velocity of the 0.7
kg cart? (Disregard the mass of the spring.) a. | 15 m/s to the right | c. | 7 m/s to the right | b. | 15 m/s to the
left | d. | 7 m/s to the
left | | | | |
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17.
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Two billiard
balls collide. Identify the type of collision. a. | perfectly inelastic | c. | inelastic | b. | perfectly elastic | d. | elastic | | | | |
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18.
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A child with
a mass of 23 kg rides a bike with a mass of 5.5 kg at a velocity of 4.5 m/s to the south. Compare the
momentum of the child with the momentum of the bike. a. | The bike has a greater
momentum than the child. | b. | Both the child and the bike have the same
momentum. | c. | Neither the child nor the bike has momentum. | d. | The child has a greater
momentum than the bike. | | |
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19.
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A billiard
ball collides with a stationary identical billiard ball in an elastic head-on collision. After the
collision, which is true of the first ball? a. | It maintains its initial velocity. | c. | It comes to rest. | b. | It has one-half its
initial velocity. | d. | It moves in the
opposite direction. | | | | |
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20.
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Which of the
following statements about the conservation of momentum is NOT correct? a. | Momentum is conserved
for a system of objects pushing away from each other. | b. | Momentum is not
conserved for a system of objects in a head-on collision. | c. | The total momentum of a
system of interacting objects remains constant regardless of forces between the
objects. | d. | Momentum is conserved when two or more interacting objects push away
from each other. | | |
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21.
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Which of the
following best describes the kinetic energy of each object after a two-body collision if the momentum
of the system is conserved? a. | must be less | c. | might also be conserved | b. | must also be
conserved | d. | is doubled in
value | | | | |
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22.
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An ice
skater initially skating at a velocity of 3 m/s speeds up to a velocity of 5 m/s. The momentum of the
skater a. | remains the
same. | c. | increases. | b. | becomes zero. | d. | decreases. | | | | |
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23.
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Which of the
following situations is an example of change in momentum? a. | A tennis ball is hit
into a net. | b. | An airplane flies into some scattered white
clouds. | c. | A helium-filled balloon rises upward into the
sky. | d. | A bicyclist rides over
a leaf on the pavement. | | |
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24.
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A person
sitting in a chair with wheels stands, causing the chair to roll backward across the floor. The
momentum of the chair a. | was zero when the person got out of the chair and increased while the
person sat. | b. | remained the same. | c. | was zero while
stationary and increased when the person stood. | d. | was greatest while the
person sat in the chair. | | |
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25.
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Two
snowballs with masses of 0.40 kg and 0.60 kg, respectively, collide head-on and combine to form a
single snowball. The initial speed for each is 15 m/s. If the velocity of the snowball with a mass of
1.0 kg is 3.0 m/s after the collision, what is the decrease in kinetic energy? a. | 110
J | c. | zero | b. | 60 J | d. | 90 J | | | | |
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26.
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A student
walks to class at a velocity of 3 m/s. To avoid walking into a door as it opens, the student slows to
a velocity of 0.5 m/s. Now late for class, the student runs down the corridor at a velocity of 7 m/s.
The student had the least momentum a. | immediately after the door opened. | b. | while running to class
at a velocity of 7 m/s. | c. | while dodging the opening door. | d. | while walking at a
velocity of 3 m/s. | | |
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27.
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A rubber
ball moving at a speed of 5 m/s hit a flat wall and returned to the thrower at 5 m/s. The magnitude
of the momentum of the rubber ball a. | was not conserved. | c. | increased. | b. | remained the same. | d. | decreased. | | | | |
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28.
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A swimmer
with a mass of 75 kg dives off a raft with a mass of 500 kg. If the swimmer’s speed is 4 m/s
immediately after leaving the raft, what is the speed of the raft? a. | 0.2
m/s | c. | 0.6
m/s | b. | 4.0
m/s | d. | 0.5
m/s | | | | |
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29.
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A billiard
ball collides with a second identical ball in an elastic head-on collision. What is the kinetic
energy of the system after the collision compared with the kinetic energy before the
collision? a. | four times as
great | c. | unchanged | b. | one-fourth as great | d. | two times as great | | | | |
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30.
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A 6.0
´ 10–2
kg tennis ball moves at a velocity of 12 m/s. The ball is struck by a racket, causing it to rebound
in the opposite direction at a speed of 18 m/s. What is the change in the ball’s
momentum? a. | –1.1
kg·m/s | c. | –0.38
kg·m/s | b. | –0.72 kg·m/s | d. | –1.8 kg·m/s | | | | |
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31.
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Which of the
following best describes the momenta of two bodies after a two-body collision if the kinetic energy
of the system is conserved? a. | must also be conserved | c. | might also be conserved | b. | must be
less | d. | is doubled in
value | | | | |
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32.
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Each croquet
ball in a set has a mass of 0.50 kg. The green ball travels at 10.5 m/s and strikes a stationary red
ball. If the green ball stops moving, what is the final speed of the red ball after the
collision? a. | 6.0
m/s | c. | 12.0
m/s | b. | 10.5
m/s | d. | 9.6
m/s | | | | |
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33.
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A 20 kg
shopping cart moving at a velocity of 0.5 m/s collides into a store wall and stops. The momentum of
the shopping cart a. | increases. | c. | remains the
same. | b. | is conserved. | d. | decreases. | | | | |
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34.
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A 0.2
baseball if pitched with a velocity of 40 m/s and is then batted to the pitcher with a velocity of 60
m/s. What is the magnitude of change in the ball’s momentum? a. | 8 kg·m/s | c. | 2 kg·m/s | b. | 4 kg·m/s | d. | 20 kg·m/s | | | | |
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35.
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The impulse
experienced by a body is equivalent to the body’s change in a. | force. | c. | kinetic
energy. | b. | momentum. | d. | velocity. | | | | |
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36.
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In an
elastic collision between two objects with unequal masses, a. | the total momentum of
the system will increase. | b. | the momentum of one object will increase by the amount that the
momentum of the other object decreases. | c. | the total momentum of the system will
decrease. | d. | the kinetic energy of one object will increase by the amount that the
kinetic energy of the other object decreases. | | |
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37.
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A moderate
force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the
grass usually does not break because for the egg dropped on the grass, a. | the time interval for
stopping is less. | c. | the change in momentum
is less. | b. | the change in momentum is greater. | d. | the time interval for stopping is greater. | | | | |
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38.
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A soccer
ball collides with another soccer ball at rest. The total momentum of the balls a. | remains
constant. | c. | increases. | b. | is zero. | d. | decreases. | | | | |
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39.
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A 2 kg mass
moving to the right makes an elastic head-on collision with a 4 kg mass moving to the left at 4 m/s.
The 2 kg mass reverses direction after the collision and moves at 3 m/s. The 4 kg mass moves to the
left at 1 m/s. What was the initial velocity of the 2 kg mass? a. | 3 m/s to the
right | c. | 4 m/s to the
left | b. | 4 m/s to the
right | d. | 1 m/s to the
left | | | | |
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40.
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A roller
coaster climbs up a hill at 4 m/s and then zips down the hill at 30 m/s. The momentum of the roller
coaster a. | is greater down the
hill than up the hill. | c. | is zero throughout the
ride. | b. | remains the same throughout the ride. | d. | is greater up the hill than down the hill. | | | | |
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41.
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An object
with a mass of 0.10 kg makes an elastic head-on collision with a stationary object with a mass of
0.15 kg. The final velocity of the 0.10 kg object after the collision is –0.045 m/s and the
final velocity of the 0.15 kg object after the collision is 0.16 m/s. What was the initial velocity
of the 0.10 kg object? a. | –1.06 m/s | c. | 0.20 m/s | b. | 0.16 m/s | d. | –0.20 m/s | | | | |
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42.
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A ball with
a mass of 0.15 kg and a velocity of 5.0 m/s strikes a wall and bounces straight back with a velocity
of 3.0 m/s. What is the change in momentum of the ball? a. | –1.20
kg·m/s | c. | –0.30
kg·m/s | b. | –7.50 kg·m/s | d. | –0.15 kg·m/s | | | | |
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43.
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After
colliding, objects are deformed and lose some kinetic energy. Identify the type of
collision. a. | perfectly
inelastic | c. | elastic | b. | inelastic | d. | perfectly elastic | | | | |
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44.
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Two skaters
stand facing each other. One skater’s mass is 60 kg, and the other’s mass is 72 kg. If the
skaters push away from each other without spinning, a. | their total momentum
decreases. | b. | their momenta are equal but opposite. | c. | the 60 kg skater
travels at a lower momentum. | d. | their total momentum doubles. | | |
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45.
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A 15 g
marble moves to the right at 3.5 m/s and makes an elastic head-on collision with a 22 g marble. The
final velocity of the 15 g marble is 5.4 m/s to the left, and the final velocity of the 22 g marble
is 2.0 m/s to the right. What is the initial velocity of the 22 g marble? a. | 5.3 m/s to the
right | c. | 4.0 m/s to the
right | b. | 5.3 m/s to the left | d. | 4.0 m/s to the left | | | | |
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46.
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Which of the
following has the greatest momentum? a. | roadrunner with a mass of 1.8 kg moving at a velocity of 6.7
m/s | b. | tortoise with a mass of
270 kg moving at a velocity of 0.5 m/s | c. | hare with a mass of 2.7 kg moving at a velocity of 7
m/s | d. | turtle with a mass of
91 kg moving at a velocity of 1.4 m/s | | |
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47.
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What
velocity must a 1340 kg car have in order to have the same momentum as a 2680 kg truck traveling at a
velocity of 15 m/s to the west? a. | 6.0 ´ 101 m/s to the east | c. | 3.0 ´ 101 m/s to the east | b. | 3.0 ´ 101 m/s to
the west | d. | 6.0 ´ 101 m/s to
the west | | | | |
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48.
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Two objects
move separately after colliding, and both the total momentum and total kinetic energy remain
constant. Identify the type of collision. a. | perfectly inelastic | c. | elastic | b. | inelastic | d. | perfectly elastic | | | | |
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49.
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In a
two-body collision, a. | kinetic energy is conserved. | b. | neither momentum nor
kinetic energy is conserved. | c. | momentum is conserved. | d. | both momentum and
kinetic energy are conserved. | | |
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50.
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A bowling
ball with a mass of 7.0 kg strikes a pin that has a mass of 2.0 kg. The pin flies forward with a
velocity of 6.0 m/s, and the ball continues forward at 4.0 m/s. What was the original velocity of the
ball? a. | 3.3
m/s | c. | 5.7
m/s | b. | 4.0
m/s | d. | 6.6
m/s | | | | |
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51.
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The change
in an object’s momentum is equal to a. | the product of the force applied to the object and the time
interval. | b. | the time interval divided by the net external
force. | c. | the net external force divided by the time
interval. | d. | the product of the mass of the object and the time
interval. | | |
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52.
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A 65.0 kg
ice skater standing on frictionless ice throws a 0.15 kg snowball horizontally at a speed of 32.0
m/s. At what velocity does the skater move backward? a. | 0.30
m/s | c. | 0.07
m/s | b. | 0.15
m/s | d. | 1.20
m/s | | | | |
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53.
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A 75 kg
person walking around a corner bumped into an 80 kg person who was running around the same corner.
The momentum of the 80 kg person a. | was conserved. | c. | decreased. | b. | remained the same. | d. | increased. | | | | |
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54.
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Which of the
following situations is an example of a visible change in momentum? a. | A hiker walks through a
spider’s web. | c. | A car drives over a
pebble. | b. | A baseball is hit by a bat. | d. | A volleyball hits a mosquito in the air. | | | | |
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55.
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A baseball
is pitched very fast. Another baseball of equal mass is pitched very slowly. Which of the following
statements is correct? a. | The slow-moving baseball is harder to stop because it has more
momentum. | b. | The fast-moving baseball is easier to stop because it has more
momentum. | c. | The fast-moving baseball is harder to stop because it has more
momentum. | d. | The slow-moving baseball is easier to stop because it has more
momentum. | | |
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56.
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A rubber
ball with a mass of 0.30 kg is dropped onto a steel plate. The ball’s velocity just before
impact is 4.5 m/s and just after impact is 4.2 m/s. What is the change in the ball’s
momentum? a. | –0.09
kg·m/s | c. | –4.0
kg·m/s | b. | –12 kg·m/s | d. | –2.6 kg·m/s | | | | |
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57.
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Paint is
splattered on a canvas. After the paint sticks to the canvas, the total momentum of the paint and
canvas a. | is
zero. | c. | is equal and
opposite. | b. | increases. | d. | decreases. | | | | |
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58.
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A clay ball
with a mass of 0.35 kg has an initial speed of 4.2 m/s. It strikes a 3.5 kg clay ball at rest, and
the two balls stick together and remain stationary. What is the decrease in kinetic energy of the
0.35 kg ball? a. | 1.6
J | c. | 6.4
J | b. | 3.1
J | d. | 4.8
J | | | | |
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59.
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Two swimmers
relax close together on air mattresses in a pool. One swimmer’s mass is 48 kg, and the
other’s mass is 55 kg. If the swimmers push away from each other, a. | their total momentum
decreases. | c. | their total momentum
doubles. | b. | their total momentum triples. | d. | their momenta are equal but opposite. | | | | |
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60.
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When
comparing the momentum of two moving objects, which of the following is correct? a. | The object with the
higher velocity will have less momentum if the masses are equal. | b. | The more massive object
will have less momentum if the velocities are the same. | c. | The less massive object
will have less momentum if the velocities are the same. | d. | The more massive object
will have less momentum if its velocity is greater. | | |
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61.
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Two objects
stick together and move with the same velocity after colliding. Identify the type of
collision. a. | elastic | c. | perfectly
inelastic | b. | perfectly elastic | d. | inelastic | | | | |
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62.
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Two objects
with different masses collide and bounce back after an elastic collision. Before the collision, the
two objects were moving at velocities equal in magnitude but opposite in direction. After the
collision, a. | the less massive object
had gained momentum. | b. | the more massive object had gained momentum. | c. | both objects lost
momentum. | d. | both objects had the same momentum. | | |
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63.
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If a force
is exerted on an object, which statement is true? a. | A large force produces a large change in the object’s momentum
only if the force is applied over a very short time interval. | b. | A small force produces
a large change in the object’s momentum. | c. | A large force always
produces a large change in the object’s momentum. | d. | A small force applied
over a long time interval can produce a large change in the object’s
momentum. | | |
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64.
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An astronaut
with a mass of 70.0 kg is outside a space capsule when the tether line breaks. To return to the
capsule, the astronaut throws a 2.0 kg wrench away from the capsule at a speed of 14 m/s. At what
speed does the astronaut move toward the capsule? a. | 3.5 m/s | c. | 0.4 m/s | b. | 5.0 m/s | d. | 7.0 m/s | | | | |
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Short Answer
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65.
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On a pool
table, a moving cue ball collides with the eight ball, which is at rest. Is it possible for both
balls to be at rest after the collision? Use the law of conservation of momentum to explain your
reasoning.
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