A thin horizontal circular disc is rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of the disc. The insect now moves along a diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc :

Options

A. continuously decreases
B. continuously increases
C. first increases and then decreases
D. remains unchanged

Answer

C

Explanation

As the insect moves along the diameter to reach its other end, moment of inertia of the disc first decreases and then increases. Therefore, by the principle of conservation of angular momentum, angular speed first increases and then decreases.