A vertical cylinder has a 10kg frictionless piston 5cm in radius. Inside the cylinder are 10 mols of helium at 2 bar and 300k. The piston is held in place with a pin. When the pin is pulled the piston rapidly rises until it can go no higher. The helium cools 10k. On taking the system to be the helium calculate q, w, and ΔU for the process.