Question

When an apple falls freely from the tree towards the ground, then its total mechanical energy throughout the fall will:

• A. increases
• B. decreases
• C. first increases and then decreases
• D. remains constant

Answer 1

The correct option is D

remains constant

Before falling, the apple only has potential energy. Once the apple starts falling, the amount of potential energy it contains decreases and the kinetic energy increases simultaneously thereby keeping the total energy constant.
Hence, from the above phenomenon, we came to know that the total energy of an isolated system will always remain constant.