A metallic circular disc having a circular hole at its centre rotates about an axis passing through its centre and perpendicular to its plane. When the disc is heated:

Options

A. its moment of inertia increases
B. its angular velocity increases.
C. its angular velocity decreases
D. its diameter increases.

Answer

A, B, C

Explanation

As the disc is heated the diamter of the hole as weill as the disc increases due to thermal expansion. Consequently the moment of inertial increases. From conservation of angular momentum `I_(1)omega_(1)=I_(2)omega_(2)` angular velocity decreases due to increase in moment of inertia.