A vertical piston/cylinder device contains 0.01 lbm of gas. The initial gas volume is 0.18 ft3 and the initial specific internal energy is 282 Btu/lbm. The piston, with a mass of 110 lbm and cross-sectional area of 0.11 ft2, is in equilibrium with the gas. The outside ambient pressure is 14.7 psia. Heat transfer in the amount of 1.85 Btu/lbm occurs from the gas to the surroundings. The final gas volume is 0.09 ft3. Assume piston movement is slow with no acceleration. Friction between the piston and cylinder is negligible.
a. Determine work [Btu/lbm] during the process (magnitude and direction)
b. Determine the specific internal energy at the final state u2 [Btu/lbm]