A ball bearing is dropped on to a rigid-hard surface from a height h. It rebounds to a height h1. Calculate the coefficient of restitution if h = 800 mm and h1 = 650 mm.

The initial height is $h = 800 \text{ mm}$.
The rebound height is $h_1 = 650 \text{ mm}$.

The coefficient of restitution, $e$, for a ball bouncing off a surface is given by the ratio of the square root of the rebound height to the square root of the initial height:

The coefficient of restitution is unitless.

The coefficient of restitution is $\text{0.901}$.