$8-79$ Air enters a two$-$stage compressor at $100$ kPa and $27\backslash$deg Cand is compressed to $625$ kPa. The pressure ratio across each stage is the same, and the air is cooled to the initial temperature between the two stages. Assuming the compression process to be isentropic$,$ determine the power input to the compressor for a mass flow rate of $0\mathrm{.}15$ kg$/$s$.$ What would your answer be if only one stage of compression were used? Answers: $27\mathrm{.}1$ kW$,31\mathrm{.}1$ kW