A turbojet is flying with a velocity of 900 ft/s at an altitude of 20,000 ft, where the ambient conditions are 7 psia and 10°F. The pressure ratio across the compressor is 13, and the temperature at the turbine inlet is 2400 R. Assume ideal operation for all components and constant specific heats for air at room temperature. The properties of air at room temperature are cp = 0.24 Btu/lbm*R and k = 1.4.
(a) The pressure at the turbine exit.
(b) The velocity of the exhaust gases, and (c) the propulsive efficiency.