. air enters the diffuser of a turbojet engine with a mass flow rate of 85 lb/s at 9 lbf/in.2 , 420°r, and a velocity of 750 ft/s. the pressure ratio for the compressor is 12, and its isentropic efficiency is 88%. air enters the turbine at 2400°r with the same pressure as at the exit of the compressor. air exits the nozzle at 9 lbf/in.2 the diffuser operates isentropically and the nozzle and turbine have isentropic efficiencies of 92% and 90%, respectively. on the basis of an air-standard analysis, calculate a. the rate of heat addition, in btu/h. b. the pressure at the turbine exit, in lbf/in.2 c. the compressor power input, in btu/h. d. the velocity at the nozzle exit, in ft/s. neglect kinetic energy except at the diffuser inlet and the nozzle exit.