Find the change in entropy of air undergoing a polytropic compression with n=1.2, if p(1) = 3 bar, T(1) = 400K, and v(2)=0.2m³/kg.

(cp = 1005 J/kg K and cv= 718 J/kg K)

Treat as a perfect gas.


so far I figured pv^n = RT

Can I use cv = R/(gamma - 1)

To find R and then v(1)

Then I think I just need to find p(2), but how?
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d.o.b in 1988, this isnt a-level!

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The answer is "c", such that c = the correct answer.

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