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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 will decrease

B

its diameter will decrease

C

its moment of inertia will increase

D

its angular speed will increase

Text Solution

Verified by Experts

The correct Answer is:
A, C
When the disc with a central hole is heated, diameter of hole is heated, diameter of hole as hole as well as outer diameter of disc both increases. As a result of this, mass of the disc will be distributed more away from its axis which means that moment of inertia will increase on heating. Now according to the law of conservation of angular momentum, as
`Iomega =` constant so `omega` will decrease.
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