A feed pump of a binary vapour cycle is of centrifugal and delivers 20m at 750rpm against a dynamic head of 8m. Determine the power

A feed pump of a binary vapour cycle is of centrifugal and delivers 20m³ at 750rpm against a dynamic head of 8m. Determine the power required to drive the motor, if the pump efficiency is 90%. If the max torque on the motor shaft is 30% more than the average torque, determine the diameter of the motor shaft. The permissible shear stress in the shaft material should not exceed 50MPa.