Two coaxial shafts a and b are connected by a single friction clutch of internal diameter 120mm and external diameter 220mm, both sides of the plate being used. shaft a is rotating at a constant angular speed of 240rev/min and b is initially stationary. shaft b has an effective moment of inertia of 12kgm2. when the clutch is engaged it takes 4s for b to reach full speed. if the coefficient of friction is 0.3 and the uniform pressure condition can be assumed, what is the required spring force and pressure and the energy dissipated during the slip period.