[QUE/SM-06004] SM-PROBLEM

Consider a cylindrical system of ideal gas with a movable piston as shown . All the wall.\, including the piston are thermally insulating. A weight W is placed on the piston. Treating this system as a closed one, Show that $$ \frac{W}{A}\,=\,\frac{2E}{3V}$$ where A is the area of cross section of the cylinder, E the energy and V the volume of gas.