Regulation tennis balls have a mass of 575 g When dropped fr

Regulation tennis balls have a mass of 57.5 g. When dropped from a height of 3.39 m they must rebound to a height of 1.42 m to be acceptable for play. What is the loss in kinetic energy when these balls rebound?

Solution

kinetic energy loss would be equal to potential energy change at max height.

So intial potential energy = mgh1 = 57.5 * 10^-3 * 9.8 * 3.39

Final potential energy = mgh2 = 57.5 *10^-3*9.8*1.42

So loss in kinetic energy = decrease in potetnial enrgy = 57.5*9.8*(3.39-1.42) = 1.1095 J