19. A machine shaft, supported on bearings having their centres 750 mm apart, transmitted 185 kW at 600 r.p.m. A gear of 200 mm and 20 tooth profile is located 250 mm to the right of left hand bearing and a 450 mm diameter pulley is mounted at 200 mm to right of right hand bearing. The gear is driven by a pinion with a downward tangential force while the pulley drives a horizontal belt having 180 angle of contact. The pulley weighs 1000 N and tension ratio is 3. Find the diameter of the shaft, if the allowable shear stress of the material is 63 MPa. [Ans. 80 mm] 20. If in the above Exercise 19, the belt drive is at an angle of 60 to the horizontal and a combined shock and fatigue factor is 1.5 for bending and 1.0 for torque, find the diameter of the shaft. [Ans. 90 mm]