A boy stands over the centre of a horizontal platform which is rotating freely with a speed of $$2$$ $$revolutions/s$$ about a vertical axis through the centre of the platform and straight up through the boy. He holds $$2$$ kg masses in each of his hands close to his body. The. combined moment of inertia of the system is $$1$$ kg×$$metre2$$. The boy now stretches his arms so as to hold the masses far from his body. In this situation, the moment of inertia of the system increases to $$2kg$$×$$metre2$$. The kinetic energy of the system in the latter case as compared with that in the previous case will

Question

Infinity Learn · Accepted Answer

I is doubled. ω is halvedRotational K.E $$=12l$$ω$$2Clearly$$, rotational $$KE$$ is decreased.

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