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During a collision with a wall, the velocity of a 0.200-kg ball changes from 20.0 m/s toward the wall to 12.0 m/s away from the wall. If the time the ball was in contact with the wall was 60.0 ms, what was the magnitude of the average force applied to the ball?


A) 40.0 N
B) 107 N
C) 16.7 N
D) 26.7 N
E) 13.3 N

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On a frictionless horizontal table, two blocks (A of mass 2.00 kg and B of mass 3.00 kg) are pressed together against an ideal massless spring that stores 75.0 J of elastic potential energy. The blocks are not attached to the spring and are free to move free of it once they are released from rest. The maximum speed achieved by each block is closest to:


A) 6.71 m/s (A) , 4.47 m/s (B)
B) 4.47 m/s (A) , 6.71 m/s (B)
C) 5.48 m/s for both
D) 6.12 m/s (A) , 5.00 m/s (B)
E) 5.00 m/s (A) , 6.12 m/s (B)

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A 2.50-kg stone is dropped from rest at a height of 3.75 m. What impulse does gravity impart to this stone from the instant it is dropped until it hits the ground, assuming negligible air resistance?

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A billiard ball traveling at 3.00 m/s collides perfectly elastically with an identical billiard ball initially at rest on the level table. The initially moving billiard ball deflects 30.0° from its original direction. What is the speed of the initially stationary billiard ball after the collision?


A) 2.00 m/s
B) 0.866 m/s
C) 1.50 m/s
D) 2.59 m/s
E) 0.750 m/s

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A car heading north collides at an intersection with a truck of the same mass as the car heading east. If they lock together and travel at 28 m/s at 46° north of east just after the collision, how fast was the car initially traveling? Assume that any other unbalanced forces are negligible.


A) 40 m/s
B) 20 m/s
C) 80 m/s
D) 30 m/s

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A 480-kg car moving at 14.4 m/s hits from behind a 570-kg car moving at 13.3 m/s in the same direction. If the new speed of the heavier car is 14.0 m/s, what is the speed of the lighter car after the collision, assuming that any unbalanced forces on the system are negligibly small?


A) 13.6 m/s
B) 10.5 m/s
C) 19.9 m/s
D) 5.24 m/s

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In a collision between two objects having unequal masses, how does magnitude of the impulse imparted to the lighter object by the heavier one compare with the magnitude of the impulse imparted to the heavier object by the lighter one?


A) The lighter object receives a larger impulse.
B) The heavier object receives a larger impulse.
C) Both objects receive the same impulse.
D) The answer depends on the ratio of the masses.
E) The answer depends on the ratio of the speeds.

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Consider two less-than-desirable options. In the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greatest impact force?


A) hitting the other car
B) hitting the brick wall
C) The force would be the same in both cases.
D) We cannot answer this question without more information.
E) None of these is true.

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A baseball is thrown vertically upward and feels no air resistance. As it is rising


A) both its momentum and its mechanical energy are conserved.
B) its momentum is not conserved, but its mechanical energy is conserved.
C) both its momentum and its kinetic energy are conserved.
D) its kinetic energy is conserved, but its momentum is not conserved.
E) its gravitational potential energy is not conserved, buts its momentum is conserved.

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A 0.500-kg ball traveling horizontally on a frictionless surface approaches a very massive stone at 20.0 m/s perpendicular to wall and rebounds with 70.0% of its initial kinetic energy. What is the magnitude of the change in momentum of the stone?


A) 18.4 kg∙m/s
B) 14.0 kg∙m/s
C) 3.00 kg∙m/s
D) 1.63 kg∙m/s
E) 0.000 kg∙m/s

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Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force   to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water? A)  The final momentum is in the direction of   but the final kinetic energy is zero. B)  The final momentum is in the direction opposite of   but the final kinetic energy is zero. C)  The final momentum is in the direction of   and the final kinetic energy is positive. D)  The final momentum is zero and the final kinetic energy is zero. E)  The final momentum is zero but the final kinetic energy is positive. to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water?


A) The final momentum is in the direction of Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force   to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water? A)  The final momentum is in the direction of   but the final kinetic energy is zero. B)  The final momentum is in the direction opposite of   but the final kinetic energy is zero. C)  The final momentum is in the direction of   and the final kinetic energy is positive. D)  The final momentum is zero and the final kinetic energy is zero. E)  The final momentum is zero but the final kinetic energy is positive. but the final kinetic energy is zero.
B) The final momentum is in the direction opposite of Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force   to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water? A)  The final momentum is in the direction of   but the final kinetic energy is zero. B)  The final momentum is in the direction opposite of   but the final kinetic energy is zero. C)  The final momentum is in the direction of   and the final kinetic energy is positive. D)  The final momentum is zero and the final kinetic energy is zero. E)  The final momentum is zero but the final kinetic energy is positive. but the final kinetic energy is zero.
C) The final momentum is in the direction of Jacques and George meet in the middle of a lake while paddling in their canoes. They come to a complete stop and talk for a while. When they are ready to leave, Jacques pushes George's canoe with a force   to separate the two canoes. What is correct to say about the final momentum and kinetic energy of the system if we can neglect any resistance due to the water? A)  The final momentum is in the direction of   but the final kinetic energy is zero. B)  The final momentum is in the direction opposite of   but the final kinetic energy is zero. C)  The final momentum is in the direction of   and the final kinetic energy is positive. D)  The final momentum is zero and the final kinetic energy is zero. E)  The final momentum is zero but the final kinetic energy is positive. and the final kinetic energy is positive.
D) The final momentum is zero and the final kinetic energy is zero.
E) The final momentum is zero but the final kinetic energy is positive.

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A car of mass 1689 kg collides head-on with a parked truck of mass 2000 kg. Spring mounted bumpers ensure that the collision is essentially elastic. If the velocity of the truck is 17 km/h (in the same direction as the car's initial velocity) after the collision, what was the initial speed of the car?


A) 19 km/h
B) 38 km/h
C) 29 km/h
D) 10 km/h

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A shell explodes into two fragments, one fragment 25 times heavier than the other. If any gas from the explosion has negligible mass, then


A) the momentum change of the lighter fragment is 25 times as great as the momentum change of the heavier fragment.
B) the momentum change of the heavier fragment is 25 times as great as the momentum change of the lighter fragment.
C) the momentum change of the lighter fragment is exactly the same as the momentum change of the heavier fragment.
D) the kinetic energy change of the heavier fragment is 25 times as great as the kinetic energy change of the lighter fragment.
E) the kinetic energy change of the lighter fragment is 25 times as great as the kinetic energy change of the heavier fragment.

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As a tile falls from the roof of a building to the ground its momentum is conserved.

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In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after are given. The collision is In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after are given. The collision is   A)  perfectly elastic. B)  partially inelastic. C)  completely inelastic. D)  characterized by an increase in kinetic energy. E)  not possible because momentum is not conserved.


A) perfectly elastic.
B) partially inelastic.
C) completely inelastic.
D) characterized by an increase in kinetic energy.
E) not possible because momentum is not conserved.

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Two objects of the same mass move along the same line in opposite directions. The first mass is moving with speed v. The objects collide, stick together, and move with speed 0.100v in the direction of the velocity of the first mass before the collision. What was the speed of the second mass before the collision?


A) 1.20v
B) 10.0v
C) 0.900v
D) 0.800v
E) 0.00v

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A small car has a head-on collision with a large truck. Which of the following statements concerning the magnitude of the average force due to the collision is correct?


A) The truck experiences the greater average force.
B) The small car experiences the greater average force.
C) The small car and the truck experience the same average force.
D) It is impossible to tell since the masses are not given.
E) It is impossible to tell since the velocities are not given.

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A uniform piece of wire, 20 cm long, is bent in a right angle in the center to give it an L-shape. How far from the bend is the center of mass of the bent wire?


A) 2.5 cm
B) 3.5 cm
C) 4.5 cm
D) 5.0 cm
E) 7.1 cm

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A time-varying horizontal force F(t) = At4 + Bt2 acts for 0.500 s on a 12.25-kg object, starting at time t = 1.00 s. In the SI system, A has the numerical value 4.50 and B has the numerical value 8.75. (a) What are the SI units of A and B? (b) What impulse does this force impart to the object?

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(a) A: N/s4 = kg ∙ m/...

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A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring


A) the lighter block will have more kinetic energy than the heavier block.
B) the heavier block will have more kinetic energy than the lighter block.
C) both blocks will both have the same amount of kinetic energy.
D) both blocks will have equal speeds.
E) the magnitude of the momentum of the heavier block will be greater than the magnitude of the momentum of the lighter block.

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