The platform in the form of a disk with a radius of 1 m rotates by inertia, making 6 rpm. At the edge of the platform is a man whose mass is 80 kg. Platform weight 200 kg. How many revolutions per minute will the platform make if a person moves to its center? The moment of inertia of a person should be calculated as the moment of inertia of a material point.

A detailed solution with a brief record of the conditions, formulas and laws used in the solution, the derivation of the calculation formula and the answer.