Air is compressed in the compressor of a turbojet engine. Air enters the compressor at 270K and 58 kPa and exits the compressor at 465 K and 350 kPa. Use, average specific heat at constant pressure (cp, avg) of air as 1.015 kJ/ kg. K and Rair =287 J/ kg. K. A) Find average value of cv for air.
B) Find mass specific enthalpy change associated with compression process.
C) Find mass specific internal energy change associated with compression process.
D) Find mass specific entropy change associated with compression process.

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.