You must purchase a centrifugal pump to circulate cooling water that will deliver $5000 \mathrm{gpm}$ at a pressure of $150 \mathrm{psi}$. If the pump is driven by an $1800 \mathrm{rpm}$ motor, what should the horsepower and torque rating of the motor be, and how large (diameter) should the pump impeller be, assuming an efficiency of $60 %$ ?