A homogeneous solid disk of radius R = 0.15 m with a weight P = 124 N rotates around a vertical axis with constant angular acceleration, and its motion is described by the equation 0 = 30t² + 2t + 1. The disk rotates under the action of a constant tangential force F= 90.2 N applied to the disk edge. (a) Find the torque of friction forces t, acting on the disk during rotation. (b) Find the time instant t when the kinetic energy Wk of the rotating disk is 3 kJ (c) What is a centripetal acceleration at this instant of the point on the disk which is at the distance 0.1 m from the axis of the rotation?

A homogeneous solid disk of radius R = 0.15 m with a weight P = 124 N rotates around a vertical axis with constant angular acceleration, and its motion is described by the equation 0 = 30t² + 2t + 1. The disk rotates under the action of a constant tangential force F= 90.2 N applied to the disk edge. (a) Find the torque of friction forces t, acting on the disk during rotation. (b) Find the time instant t when the kinetic energy Wk of the rotating disk is 3 kJ (c) What is a centripetal acceleration at this instant of the point on the disk which is at the distance 0.1 m from the axis of the rotation?