: A fixed mass of hot gas in a well-sealed piston cylinder assembly maintaining constant 1 bar pressure. The gas is then cooled by an ice pack at the bottom of the cylinder during which volume is decreased by 0.5 m3 . Measurements indicate that the internal energy of the gas inside the cylinder decreases by 60 kJ. The side wall of the cylinder is not insulated and 10 kJ of heat goes from cylinder to the surrounding atmospheric air. Assume cylinder and piston both have negligible mass and their internal energy changes are insignificant. Determine (a) energy interaction in the form of work in kJ and its direction (b) how much energy is transferred to melt the ice.