A simple pendulum has time period `2s`. The point of suspension is now moved upward accoding to relation `y = (6t - 3.75t^(2))m` where `t` is in second and y is the vertical displacement in upward direction. The new time period of simple pendulum will be

Options

A. `2s`
B. `1s`
C. `4s`
D. None of these

Answer

C

Explanation

`T_(1) = 2s = 2pisqrt((l)/(g)), T_(2) = 2pisqrt((l)/(g'))` where `g = g + (d^(2)y)/(dt^(2)) = 10 - 7.5 = 2.5 = (g)/(4) rArr T_(2) = 2pisqrt((l)/(g//4)) = 2 xx 2 = 4s`