Q.

A pendulum is hung from the roof of a sufficiently high building and is moving freely to and fro like a simple harmonic oscillator. The acceleration of the bob of the pendulum is 20ms-2 at a distance of 5 m from the mean position. The time period of oscillation is             [2018]
 

1 2π s  
2 π s  
3 2 s  
4 1 s  

Ans.

(2)

Magnitude of acceleration of a particle moving in a S.H.M. is, |a|=ω2y,  where y is amplitude.

  20=ω2(5)ω=2rad s-1

   Time period of oscillation,  T=2πω=2π2=πs