"A mass-loaded piston-cylinder system containing air is at 40 lbf/in^2" , 500 °R with a volume of 11 ft3 , while at the stops V = 38 ft3 . An air supply line at 1040 °R is connected to the system by a valve. The valve is then opened until a final pressure of 55 lbf/in.2 at T = 620 °R is reached inside the piston-cylinder assembly. Determine (a) the air mass that enters, (b) the work done in Btu, and (c) the heat transfer in Btu. (Hint: The air is modeled as an ideal gas and the pressure is constant until it reaches to the final pressure).