A cylinder/piston contains 5 lbm of water at 80 lbf/in.2, 1000 F. The piston has cross-sectional area of 1 ft2 and is restrained by a linear spring with spring constant 60 lbf/in. The setup is allowed to cool down to room temperature due to heat transfer to the room at 70 F. Calculate the total (water and surroundings) change in entropy for the process.
State 1: v1 = 10.831 ft3/lbm, u1 = 1372.3 btu/lbm,
s1 = 1.9453 Btu/lbm R
State 2: T2 & on line in P-v diagram.
