Question:
Collisions between ping pong balls and paddles are not perfectly elastic. Suppose that if a player holds a paddle still and drops a ball on top of it from any height h, it will bounce back up to height h/2. To keep the ball bouncing steadily, the player moves the paddle up and down, so that it is moving upward with speed 1.0m/s whenever the ball hits it. What is the height to which the ball is bouncing?
(A) 0.21m.
(B) 0.45m.
(C) 1.0m.
(D) 1.7m.
(E) There is not enough information to determine the height.