Question

A footballer kicked the ball and it was caught by the opposing goalkeeper, 4 metres above the ground. The hall was travelling at 10m/s. Calculate the potential energy of the ball just before it was caught

Answer 1

The potential energy depends on the height. At the height of 4 m, the potential energy is

$$E=mgh=m·9.8·4=39.2m\text{ J}.$$

$m$ is the mass of the ball.