A turbojet aircraft flies with a velocity of 900 km/h at an altitude where the air temperature and pressure are -35 degrees C and 40 kPa. Air leaves the diffuser at 50kPa with a velocity of 15 m/s, and combustion gases enter the turbine at 450 kPa and 950 degrees C. The turbine produces 500 kW of power, all of which is used to drive the compressor. Assuming an isentropic efficiency of 83 percent for the compressor, turbine, and nozzle, and using variable specific heats, determine (a) the pressure of combustion gases at the turbine exit, (b) the mass flow rates of air through the compressor, (c) the velocity of the gases at the nozzle exit, and (d) the propulsive power and the propulsive efficiency for this engine.