Energy during a fall

A ball of $1.5\ \text{kg}$ is dropped from $18\ \text{m}$. You will make the program find its potential and kinetic energy at each height on the way down, and its speed at the ground. Then it draws the two energies and their total.

The idea. With no air, the potential energy lost becomes kinetic energy, so $PE + KE$ stays the same, and at the ground $v = \sqrt{2gH}$.

Your tasks.

1. Inside the loop, work out PE at the height h, in joules.
2. Inside the loop, work out KE: the potential energy lost since the top, in joules.
3. Find v, the speed just before the ball lands, in m/s.