JEE MAIN - Physics (2002 - No. 41)
A child swinging on a swing in sitting position, stands up, then the time period of the swing will
increase
decrease
remains same
increases of the child is long and decreases if the child is short
Explication
KEY CONCEPT : The time period $$T = 2\pi \sqrt {{\ell \over g}} $$ where
$$\ell $$ $$=$$ distance between the point of suspension and the center of mass of the child. This distance decreases when the child stands
$$\therefore$$ $$T' < T$$ i.e., the period decreases.
$$\ell $$ $$=$$ distance between the point of suspension and the center of mass of the child. This distance decreases when the child stands
$$\therefore$$ $$T' < T$$ i.e., the period decreases.