HElium is contained in a closed cylinder fitted tightly with a piston. The initial conditions of the helium are 7 ft^3, 80 psia, and 100 F. The helium expands reversibly according to process PV^1.5=C until the pressure reaches 15 pisa. Calculated the work (Btu) & heat transfer (Btu) during the process. Assume that helium is an ideal gas.