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A uniform metallic rod rotates about it...

A uniform metallic rod rotates about its perpendicular bisector with constant angualr speed. If it is heated uniformly to raise its temperature slightly, then

A

its speed of rotation increases

B

its speed of rotation decreases

C

its speed of rotation remains same

D

its speed increases because its moment of inertia increases

Text Solution

Verified by Experts

The correct Answer is:
B
Moment of inertia of the rod about a perpendicular bisector as axis is
`I = M[(L^(2))/(12)+(r^(2))/(4)]`
When a metallic rod is heated, it expands in length. Its moment of inertia I increases. According to law of conservation of angular momentum
`I omega = a` constant or `omega prop (1)/(I)`
As I increases, `omega` decreases.
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