Question

The hanging bob of a simple pendulum is displaced to one extreme position B and then released. It swings towards centre position A and then to the other extreme position C. In which position does the bob have:
(a) Maximum potential energy?
(b) Maximum kinetic energy?
​Give reason for your answer.

Answer 1

A simple pendulum oscillates about its mean position. The mechanical energy throughout the motion remains conserved. At extremes positions, the velocity of the bob becomes zero and the energy becomes purely potential. At mean position, the energy becomes purely kinetic and potential energy becomes zero. Hence, we can conclude:

(a) Bob has the maximum potential energy at the extreme position.

(b) Bob has the maximum kinetic energy at the mean position,