A pendulum of length `1 m` hangs from an inclined wall. Suppose that this pendulum is released at an initial angle of `10^(@)` and it bounces off the wall elastically when it reaches an angle of `-5^(@)` as shown in the figure. Take `g = pi^(2) m//s^(2)`. The period of this pendulum is (in second)

Options

A. `2//3`
B. `3//2`
C. `3//4`
D. `4//3`

Answer

D

Explanation

We take `theta = (10^(@)) cos (pit)`, calculate t when `theta = -5^(@)`. This gives `t = 2//3 (s)`. The period is 2 times this.