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A uniform metallic rod rotates about it...

A uniform metallic rod rotates about its perpendicular bisector with constant angular 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

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The correct Answer is:
B
When a metallic rod is heated, it expands. Its moment of inertia `(I)` about a perpendicular bisector increases. According to law of conservation of angular momentum, its angular speed `(omega)` decreases, since `omega prop (1)/(I)` (according to law of conservation of angular momentum).
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