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Question :
51. A 0.10-kg object moving initially with a velocity of : 2102126

51. A 0.10-kg object moving initially with a velocity of +0.20 m/s makes an elastic head-on collision with a 0.15-kg object initially at rest. What percentage of the original kinetic energy is retained by the 0.10-kg object?

A. 4%

B. -4%

C. 50%

D. 96%

52. Two billiard balls have velocities of 2.0 m/s and -1.0 m/s when they meet in an elastic head-on collision. What is the final velocity of the first ball after collision?

A. -2.0 m/s

B. -1.0 m/s

C. -0.5 m/s

D. +1.0 m/s

53. Two objects, one less massive than the other, collide elastically and bounce back after the collision. If the two originally had velocities that were equal in size but opposite in direction, then which one will be moving faster after the collision?

A. The less massive one.

B. The more massive one.

C. The speeds will be the same after the collision.

D. There is no way to be sure without the actual masses.

54. In a partially elastic collision between two objects with unequal mass:

A. the velocity of one will increase by the amount that the velocity of the other decreases.

B. the momentum of one will increase by the amount that the momentum of the other decreases.

C. the energy of one increases by the amount that the energy of the other decreases.

D. the total momentum of the system will decrease.

55. A 7.0-kg bowling ball strikes a 2.0-kg pin. The pin flies forward with a velocity of 6.0 m/s; the ball continues forward at 4.0 m/s. What was the original velocity of the ball?

A. 4.0 m/s

B. 5.7 m/s

C. 6.6 m/s

D. 3.3 m/s