A vertical cylindrical container contains some helium gas that is in thermodynamic equilibrium with the surroundings. The gas is confined by a movable heavy piston. the piston is slowly elevated a distance H from its equilibrium position and then kept in the elevated position long enough for the thermodynamic equilibrium to be reestablished. after that,the container is insulated and then the piston is released. after the piston comes to rest,what is the new equilibrium position of the piston? This question is quite complex to me and i am totally at a loss. i know the second process is an adiabatic process but not sure about the first,the answer is the piston dropped by 0.6H to 0.4H at the new equilibrium,but who can show me how to arrive at it?