An oil pump is drawing 35 kW of electric power while pumping oil with p= 860 kg/m³ at a rate of 0.1 m³/s. The inlet and outlet diameters of the

pipe are 8 cm and 12 cm, respectively. If the pressure rise of oil in the pump is measured to be 400 kPa and the motor efficiency is 90 percent,determine the mechanical efficiency of the pump.