)a vertical piston/cylinder device contains 0.01 lbm of gas. the gas has an initial volume of 0.18 ft3 and initial specific internal energy of 282 btu/lbm. the piston, with a mass of 110 lbm and cross-sectional area of 0.11 ft2 , is in equillibrium with the gas. the outside ambient pressure is 14.7 psia. the gas now undergoes a process in which the volume increases to 0.4 ft3 . the final specific internal energy is 316 btu/lbm. assume a quasiequillibrium process in which piston movement is slow with no acceleration. friction between the piston and cylinder is negligible.