An insulated cylinder of cross-sectional area .010m2 contains a monatomic ideal gas at T= 280 K. The system is in a vacuum chamber. Initally the gas supports the piston at a height of .20m. Sand is slowly placed onto the piston. When 10 kg of sand has been added, the piston has fallen .05m. How much gas is in the cylinder? what is the mass of the piston? Im having difficulty getting started Can i equate the work done by gravity with the work done by the gas?