3.0 kg of air is initially at 200 kPa and 10oC. The air is compressed in a polytropic process, following the relationship PVn = constant. The air is compressed until the volume is 0.40 m3. Determine the work done and the final temperature of the air for values of n of 1.0, 1.1, 1.2, 1.3, and 1.4, and plot the work as a function of n.
Given: m = 3.0 kg; P1 = 200 kPa; T1 = 10oC = 283 K; V2 = 0.40 m3
What will be an ideal response?
For air, R = 0.287 kJ/kg-K
From the ideal gas law, V1 = mRT1/P1 = 1.218 m3
For a polytropic process with n = 1: 
For a polytropic process with n ? 1: 
To solve for P2, use P2 = P1 (V1/V2)n
The following values can be found from these two equations:
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