A heavy wheel can rotate on a fixed axle without friction, the entire mass of which is concentrated in the rim (Fig. 53). The radius of the wheel is R, its mass is M. A light pulley of radius r is connected to the wheel, on which a thread is wound. A load of mass m hangs at the end of the thread. What speed will the mass m have after it has fallen a distance R? At the top point the speed of the load was zero.

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