Question

A rubber ball is dropped from rest at a fixed height. It bounces off a hard floor and rebounds upward, but it only reaches 90% of its original fixed height. What is the best way to explain the loss of kinetic energy of the ball during the collision?
a. Energy was required to deform the ball’s shape during the collision with the floor.
b. Energy was lost due to work done by the ball pushing on the floor during the collision.
c. Energy was lost due to friction between the ball and the floor.
d. Energy was lost due to the work done by gravity during the motion.

Answer 1

Energy was lost due to work done by the ball pushing on the floor during the collision.

Answer:

Option B

Explanation:

As per Newton's third law of motion, every action has an equal and opposite reaction. So if an object is made to drop from height to reach the floor, then its kinetic energy when the object is moving will be transferred to the floor on hitting the floor. Thus, this loss of kinetic energy will lead to rebounding of ball to 90% of original fixed height and not to the same height. So the point the ball hits the floor, the kinetic energy of the ball will be utilized to push on the the floor such that the ball can rebound itself. Hence, it is stated that the loss of kinetic energy of the ball during collision is because it is lost due to work done by the ball pushing on the floor during the collision.