73. The disc of radius R = 20 cm and m = mass of 7 kg rotates according to the equation φ = A + Bt + Ct3, where A = 3 radians; B = -1 rad / s; C = 0.1 rad / c3. Find a law by which varies the torque acting on the drive. Determine the torque M at time t = 2 s.

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