Suppose a ball is dropped from shoulder height, falls, makes a perfectly elastic collision with the floor, and rebounds to shoulder height. Compare the magnitudes of the impulses delivered to the ball by gravity and by the floor during this entire motion.
A) The impulse delivered by the floor is half as large as the impulse delivered by gravity.
B) The impulse delivered by the floor is twice as large as the impulse delivered by gravity.
C) The two impulses have the same magnitude.
D) The floor delivers an upward impulse, but gravity does not deliver a total impulse.

Question

Quizplus · Accepted Answer

According to the law of conservation of momentum, the impulse imparted on the ball by gravity must be equal and opposite to the impulse imparted on the ball by the floor. Since the ball returns to its original height, the magnitudes of these two impulses must be equal, so the answer is C.

Suppose a Ball Is Dropped from Shoulder Height, Falls, Makes