Question

in an air motor cylinder the compressed air has an internal energy of 450 kj/kg at the beginning of the expansion and an internal energy of 220kj/kg after expansion.of the work done by air during the expansion under a pressure of 50Pa by 6×10^7cm³ per 10kg.calculate the heat flow to and fro from the cylinder

Answer 1

$Q=A+\Delta U=\frac{pV}m+U_2-U_1=-200~\frac{kJ}{kg}.$