For a control volume, cv, σ(mass in)-σ(mass out) =? a)-0 b)- constant c)- change of energy contained in the cv d)- change of mass contained in the cv e)- rate of change of energy contained in the cv

An engine runs on the ideal diesel cycle. the cycle has a compression ratio of 20 and a cutoff ratio of 2. the highest temperature in the cycle is 1200 k. if the heat into the system is 300 kj/kg of working fluid and using variable specific heats determine the work produced per mass of working fluid