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A metallic circular disc having a circul...

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:

A

its angular speed increases

B

its angular speed decreases

C

its moment of inertia increases

D

its moment of inertia decreases

Text Solution

Verified by Experts

The correct Answer is:
B, C
Diameter of disc as well as that of the hole increases due to thermal expansion. As a result, moment of inertia of circular disc will increase and from conservator of angular momentum, angular speed decreases.
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Knowledge Check

  • The moment of inertia of a copper disc, rotating about an axis passing through its centre and perpendicular to its plane

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