Which of the diagrams shown in figure represents variation of total mechanical energy of a pendulum oscillating in air as function of time?

Options

A.
B.
C.
D.

Answer

C

Explanation

(c ) When a pendulum oscillates in air, it will lose energy continuously in overcoming resistance due to air. Therefore, total mechanical energy of the pendulum decreases continously with time.
The variation is correctly represented by curve (c ).