An automotive plate clutch consists of two pairs of contacting surfaces. The torque transmitting capacity of the clutch is 550 N-m. The coefficient of friction is 0.25 and the permissible intensity of pressure is 0.5 MPa. The outer diameter of the friction disk is 250 mm. Assume uniform wear. 15. The inner diameter of the friction disk is (approximately) (a) 117 mm (c) 157 mm (b) 134 mm (d) 174 mm 16. The spring force required to keep the clutch in engaged position is (approximately) (a) 7.8 kN (b) 8.1 kN (c) 10.4 kN (d) 12.5 kN