99. The body of mass m = 4 kg, mounted on a horizontal axis to oscillate with a period T1 = 0,8 s. When the axis has been planted disk so that its axis coincides with the axis of oscillation of the body, the oscillation period T2 was equal to 1.2. Radius R disc is 20 cm, weight equal to the weight of his body. Find the moment of inertia J of the body relative to the axis of oscillation.

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