A different type of reversible heat engine. In this problem, we consider a heat engine whose working substance is an ideal gas. In other words, take it as a given that its equation of state in equiLiBrium is the ideal gas law pV - nRT = 0 and that its internal energy U depends only on the temperature T, not on p or V. You should also assume that the gas has a constant (positive) heat capacity Cy (which is true to a good approximation for almost all gases that can be treated as ideal). The gas starts at a temperature Tand volume V1 and goes through the following cycle: ⋅ The gas cools at constant volume to a temperature T.