4-17 A frictionless piston-cylinder device contains 5 kg of nitrogen at 100 kPa and 250 K. Nitrogen is now compressed slowly according to the relation PV1.4 = constant until it reaches a final temperature of 450 K. Calculate the work input during this process. Answer: 742 kJ N₂ PV1.4 = const. FIGURE P4-17 the pressive of a 4 cy 1-