Question

When a stone falls freely towards the earth, its total energy ?

• A. First decreases and then becomes zero
• B. Remains constant
• C. Increases
• D. Decreases

Answer 1

Answer: (B)

Remains constant

Since the ball is in free-fall, the only force acting on it is gravity. Therefore, we can use the principle of conservation of mechanical energy - initially the ball has potential energy and no kinetic energy. As it falls, its total energy (the sum of the KE and the PE) remains constant and equal to its initial PE. when reaches the ground there is no PE only KE I.E., Equal to initial PE
Hence, option B is correct.