Q.

A simple pendulum has time period T1. The point of suspension is now moved upward according to the relation y=Kt2, (K=1 m/s2) where y is the vertical displacement. The time period now becomes T2. The ratio T12T22 is          (g=10 m/s2)                [2005]

1 5/6  
2 6/5  
3 1  
4 4/5  

Ans.

(2)

Given : y=kt2

  dydt=v=2kt     and,       d2ydt2=a=2k

or  ay=2 m/s2    (k=1m/s2 given)

We know that  T=2πlg  or,  T1=2πlg

    T2=2πlg+ay

  T12T22=g+aygT12T22=1210=65