Air is compressed by an adiabatic compressor from 100 kpa and 20°c to 1.8 mpa and 400°c. air enters the compressor through a 0.15-m2 opening with a velocity of 30 m/s. it exits through a 0.086-m2 opening. calculate the mass flow rate of air and the required power input. the constant pressure specific heat of air at the average temperature of 210°c = 483 k is cp = 1.026 kj/kg·k. the gas constant of air is r = 0.287 kpa·m3/kg·k.