Question

A child swinging on swing in sitting position stands up. The time period of the swing will(a) increase(b) decrease(c) remain same(d) increase if the child is tall and decrease if the child is short.

Answer 1

Your answer is !! (c) remain same !!

Answer 2

A child swinging on swing in sitting position.

Let the effective length of the string be l.

Then, Time period of a swing can be given same as pendulum,

T = 2π√(l/g)

Now, The boy stands up. So, length of pendulum decreases,

Then, T (new) = 2π √(l(new) / g

Since, l(new) < l (initial).

So, T(new) < T( initial).

Therefore,The time period of the swing will  decrease.