Q88 / 90 · JEE Main 2023 (31 Jan Shift 2) · Physics

A ball is dropped from a height of $20 m$ . If the coefficient of restitution for the collision between ball and floor is $0.5$ , after hitting the floor, the ball rebounds to a height of ______ $m$ .

Correct answer: 5

Solution

As we know $h^{'} = e^{2} h$ , where $h^{'} =$ height after the collision, $h =$ height before the collision and $e =$ coefficient of restitution.

Therefore,

$h^{'} = {(0.5)}^{2} \times 20 m = 5 m$

Hence, the correct answer is 5.