85. A person weighing m = 60 kg, standing on the edge of the horizontal platform radius R = 1 m and a mass M = 120 kg, coasting about a fixed vertical axis with the frequency n1 = 10 min-1, it moves to the center. Assuming a uniform platform round disc, but a man - a point mass, determine the work done by the person in the transition from the edge of the platform to its center.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)