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A boy stands at the center of a turntable, which has a moment of inertia of...

A boy stands at the center of a turntable, which has a moment of inertia of 1.50 kg·m2 about an axis through its center. The boy's moment of inertia about the same axis, when he holds his arms in, is 1.10 kg·m2; when he sticks his arms straight out, his moment of inertia is 1.80 kg·m2. He and the turntable are initially rotating at a rate of 2.00 rad/s, with his arms extended.

            a.         He pulls in his arms. What is his new angular speed?

            b.         What is the change in the BOY'S kinetic energy when he pulls his arms in?

            c.         If each of the boy's hands has a mass of .750 kg, and is 70.0 cm from his body when his arms are extended, what is the centripetal force on one of his hands when his arms are sticking out?

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