A system consists of nitrogen (N2) in a piston-cylinder assembly, initially at p1 = 20 lbf/in2.and occupying a volume of 2.5ft3. The nitrogen is compressed to p2 = 100 lbf/in2 and final volume of 1.5 ft3. During the process the relation between pressure and volume is linear. Determine the pressure in lbf/in2, at an intermediate state where the volume is 2.1 ft3, and sketch the process on a graph of pressure versus volume.