Question

A child swinging on a swing in sitting position, stands up, then the time period of the swing will
(a) increase
(b) decrease
(c) reamains same
(d) increases if the child is long and decreases if the child is short.

Answer 1

(b) : Time period will decrease.
When the child stands up, the center of gravity is shifted upwards and so a length of swing decreases.

T = 2π√(l/g).