4. The impeller of a centrifugal pump is of 300 mm diameter and 50 mm width at the periphery, and has blades whose tip angle incline backwards 60 from the radius. The pump delivers 17 m/min. of water and the impeller rotates at 1000 r.p.m. Assuming that the pump is designed to admit radially, calculate: (i) Speed and direction of water as it leaves the impeller, (ii) Torque exerted by the impeller on water, (iii) Shaft power required, and (iv) Lift of the pump. Take, mechanical efficiency = 95% and hydraulic efficiency= 75%.