Gas in a closed system undergoes the power cycle as shown in the p-v diagram below as described by 1->2 is a constant pressure process, 2-> 3 is a constant volume process and 3 -> 1 is a pV = const. process. The internal energy U1 = U2 = 30 kJ/kg and U3 = 50 kJ. The changes in kinetic and potential energies are zero. Determine
a) the work for each process(W12, W23, W31) in kJ
b) the heat transfer for each process(Q12, Q23, Q31) in kJ
c) the overall efficiency of the cycle