What a physical system is and give an example.

A physical system is a portion of the physical universe chosen for analysis. For example, the water in a lake, the water in half of a lake, or an individual molecule of water in the lake can each be considered a physical system. An isolated system is one that has negligible interaction with its environment.

Explanation:

the potential energy is higher as the object when it falls will have more room to accelerate using kinetic energy