Question

The variation of amplitude A with respect to time t is shown as

Answer 1

Correct option  (b)

Explanation:

Ideal case: no damping: the amplitude remains constant. (third graph)

Practical case: damping is present: amplitude decreases exponentially. Assuming the damping force is directly proportional to velocity of the bob. We can write the amplitude : A = A₀ e- bt/2m

 Here b is damping constant and m is mass of the pendulum bob.

So the correct option is (b)