Multiple ChoiceIdentify the choice that best completes the
statement or answers the question.
net momentum before = net momentum after
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1
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A 4.0-kg ball has a momentum of 20.0 kg·m/s. What is the ball's
speed?
a. | 80.0 m/s | b. | 20.0 m/s | c. | 0.2
m/s | d. | 5.0 m/s | e. | none of the
above |
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2
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The reason padded dashboards are used in cars is that they
a. | increase the time of impact in a collision. | b. | look nice and feel
good. | c. | decrease the momentum of a collision. | d. | decrease the impulse in a
collision. | e. | increase the force of impact in a collision. |
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3
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The momentum of an object is defined as the object's
a. | velocity times the time interval. | b. | force times the time
interval. | c. | mass times its velocity. | d. | mass times it acceleration. | e. | force times its
acceleration. |
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4
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A collision is considered elastic if
a. | after the collision, the objects have the same shape as before the
collision. | b. | the objects that collide don't get warmer. | c. | the objects
don’t stick together. | d. | there is no lasting
deformation. | e. | all of the above |
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5
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A 3-kg ball is thrown at 7 m/s. What is the ball's momentum?
a. | 7 kg·m/s | b. | 49 kg·m/s | c. | 21
kg·m/s | d. | 3 kg·m/s | e. | none of the
above |
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6
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A cannon recoils from launching a cannonball. The speed of the cannon's
recoil is small because the
a. | impulse on the cannon is less than the impulse on the cannonball. | b. | force against the
cannon is relatively small. | c. | cannon has far more mass than the
cannonball. | d. | momentum of the cannon is unchanged. | e. | none of the
above |
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7
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The white ball below strikes the black 8-ball below traveling at 3 m/s. Assuming
that each of the balls has the same mass, what is the velocity of the 8-ball after the
collision?
a. | 3 m/s | c. | 1 m/s | b. | 6m/s | d. | 0 m/s |
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8
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A ball is moving at 6.0 m/s and has a momentum of 24.0 kg·m/s. What is the
ball's mass?
a. | 0.3 kg | b. | 24.0 kg | c. | 144.0
kg | d. | 4.0 kg | e. | none of the
above |
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9
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A 50-kg child on a skateboard is traveling at 7.0
m/s. What is the resultant momentum?
a. | 350 kg·m/s | b. | 0.14 kg·m/s | c. | 50
kg·m/s | d. | 350 kg·m/s |
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10
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The momentum change of an object is equal to the
a. | force acting on it times its velocity. | b. | object's mass times the force acting on
it. | c. | force acting on it. | d. | velocity change of the
object. | e. | impulse acting on it. |
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11
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A 8-kg ball is thrown at 5 m/s. What is the ball's momentum?
a. | 25 kg·m/s | b. | 8 kg·m/s | c. | 5
kg·m/s | d. | 40 kg·m/s | e. | none of the
above |
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12
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When these two freight cars of different mass
collide and couple, what will be their resultant velocity?
a. | 10 m/s | b. | 1.0 m/s | c. | 2
m/s | d. | 50 m/s |
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13
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A cannonball shot from a long-barrel cannon travels faster than one shot from a
short-barrel cannon because the cannonball receives a greater
a. | impulse. | b. | force. | c. | both A and
B | d. | neither A nor B |
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14
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If the momentum of an object changes and its mass remains constant,
a. | its velocity is changing. | b. | there is a force acting on
it. | c. | it is accelerating (or decelerating). | d. | all of the above | e. | none of the
above |
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15
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Momentum of a system is conserved only when
a. | there is no net external force acting on the system. | b. | the system has zero
momentum. | c. | the system is not moving. | d. | there are no forces acting on the
system. | e. | there are no internal forces acting on the system. |
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16
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A cannon fires a cannonball. The speed of the cannonball will be the same as the
speed of the recoiling cannon
a. | because velocity is conserved. | b. | because both velocity and momentum are
conserved. | c. | because momentum is conserved. | d. | if the mass of the cannonball equals the mass
of the cannon. | e. | none of the above |
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17
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A table tennis ball launcher is fired. Compared to the force on the ball, the
force on the launcher is
a. | the same. | b. | smaller. | c. | larger. |
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18
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A ball is moving at 7.0 m/s and has a momentum of 49.0 kg·m/s. What is the
ball's mass?
a. | 7.0 kg | b. | 0.1 kg | c. | 49.0
kg | d. | 343.0 kg | e. | none of the
above |
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19
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Compared to a sports car moving at 30 miles per hour, the same sports car moving
at miles per hour has
a. | twice as much momentum. | b. | four times as much
momentum. | c. | the same momentum. |
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20
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A 2.0-kg ball has a momentum of 6.0 kg·m/s. What is the ball's
speed?
a. | 0.3 m/s | b. | 3.0 m/s | c. | 12.0
m/s | d. | 6.0 m/s | e. | none of the
above |
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21
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Which has more momentum, a large truck moving at 30 miles per hour or a small
truck moving at 30 miles per hour?
a. | The large truck | b. | Both have the same
momentum. | c. | The small truck |
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