Acentrifugal pump is required to deliver 33,6 m^3/s of water per minute against a head of 12 metres when driven at 750 r/min. the velocity of flow through the impeller is constant at 163 metres per minute. the estimated manometric efficiency will be 80% and the internal head loss in the pump calculated at 0,0276 v22 metres where v2 is in m/s. calculate : 1)- the effective area of the impeller at exit. 2)- the diameter of the impeller at exit. 3)- the outlet vane angle.