According to the question, we draw the following situation
As, the point of suspension is moving upward according to the relation
y=λt2 =2λt Further,
=2λ= upward acceleration
a Here,
2λ is the acceleration of point of suspension. The bob experiences a downward reaction force.
Hence, the new time period
T′=2π√ .......(i)
Whereas the time period of simple pendulum,
T=2π√ ......(ii)
By comparing Eqs. (i) and (ii), we get
T′<T Hence, the new time period is less than
T.