1. A piston/cylinder contains air at 2500 R, 2200 lbf/in.2, with V1 = 1 in.3, Acyl = 1 in.2, as shown in Fig. P6.92. The piston is released, and just before the piston exits the end of the cylinder, the pressure inside is 30 lbf/in.2. If the cylinder is insulated, what is its length? How much work is done by the air inside?
2. A 25-ft3 insulated, rigid tank contains air at 110 lbf /in.2, 75 F. A valve on the tank is opened, and the pressure inside quickly drops to 20 lbf/in.2, at which point the valve is closed. Assuming the air remaining inside has undergone a reversible adiabatic expansion, calculate the mass withdrawn during the process.