Question

The tree is 15 metres high and the cat has a mass of 5 kilograms. How much potential energy does the cat have?

Answer 1

The cat on the ground has zero potential energy:

$$E_0=mgh=5·9.8·0=0.$$

The cat on top of the tree has the following potential energy:

$$E_{15}=mgH=5·9.8·15=0.=735\text{ J}.$$