A massless circular disk is placed flat on a horizontal frictionless table. Three masses are placed equidistant from the centre of the disk, and fixed to the disk. The middle and outer mass are acted on by opposing forces as indicated. The radius from the axis of rotation is 12 m. Find: The total (net) torque on the system. The angular acceleration of the system. Assuming a constant acceleration from rest, the angular velocity after 5 seconds. The number of revolutions completed after 20 seconds of constant acceleration. [40 marks]