(Solved): ( 25 points) Air is contained in a vertical piston-cylinder assembly with a piston mass of 20kg a ...

( 25 points) Air is contained in a vertical piston-cylinder assembly with a piston mass of $$20\mathrm{kg}$$ and a face area of $$0.005{\mathrm{m}}^2$$. The mass of the air is $$2.5\mathrm{g}$$ and it occupies a volume of $$0.0025{\mathrm{m}}^3$$. The atmosphere exerts a pressure of $$100\mathrm{kPa}$$ on the top of the piston. The volume of the air decreases to $$0.001{\mathrm{m}}^3$$ as $$1\mathrm{kJ}$$ of energy is slowly removed by heat transfer. Friction between the piston cylinder can be ignored and $$\mathrm{g}=9.8\mathrm{m}/{\mathrm{s}}^2$$. a. Determine the work done by the air on the piston during the process ( $$\mathrm{kJ})$$. b. Find the change in internal energy of the air $$(\mathrm{kJ}/\mathrm{kg})$$.