At steady state, a well-insulated compressor takes in air at
60f,14.2lbf/in^2, a temperature of 80f, and a volumetric flow rate
of20ft^3/s. air exits the compressor at 50lbf/in^2. heat
transferfrom the compressor to its surroundings occurs at a rate of
20.5btuper lb of air flowing. if the compressor power input is
105hp, determine the exit temperature, in f.

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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.