Air enters a two-stage compressor at 100 kPa and 27 degrees C and is compressed to 625 kPa. The pressure ration across each stage is the same (is this optimum?), and the air is cooled to the intial tempearure between stages. Assuming the compression process is isentropic, determine the power input to the compressor for a mass flow rate of 0.15 kg/s. If only a single stage were used what would the power requirement be?