air undergoes three processes in series:

Process 1-2: polytropic compression, with n=1.3, from p1=100 kPa, v1=.04 m^3/kg to v2=.02 m^3/kg

Process 2-3: isobaric process to v3=v1

Process 3-4: isometric process to p4=350 kPa

Sketch the process on a p-v diagram and determine the net work per unit mass of the air.

If you can give a DETAILED answer for one out of two of these, I will give you the points.