Question
A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly
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Answer
When a metallic rod is heated it expands. Its moment of inertia $(1)$ about a perpendicular bisector increases. Ac cording to law of conservation of angular momentum, its angular speed ( $\omega$ ) decreases, since $\omega \propto 1 / l$ (ac cording to law of conservation of angular momentum).
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