A piston cylinder assembly whose piston initially rests on stops contains 0.5 Kg of helium gas @ 100Kpa and 25 degrees Celsius. The mass of the piston and the effects of atmospheric pressure acting on the piston are such that a pressure of 500 Kpa is required to to raise it. How much energy must be transferred by heat to the helium, in KJ before the piston starts to rise? Cp=2.5 R