P. 4302. There is some Oxygen gas in a vertical, long enough, metal, cylinder, above a piston of mass m=60 kg, and of cross section A=2 dm2. The cylinder is closed at its top and the piston hangs on a thread of length 0=11.2 dm. The initial pressure and temperature of the gas are equal to the pressure and temperature outside the cylinder, p0=105 Pa T0=273 K, respectively. The wall of the cylinder is a good heat conductor, and the piston can move in the cylinder without friction. By what amount will the total energy of the system change if the thread breaks?