A Brayton cycle with a pressure ratio of 12 operates with air entering the compressor at 1...

A Brayton cycle with a pressure ratio of 12 operates with air entering the compressor at 13 psia and 20°F, and the turbine at 1000°F. Calculate the net specific work produced by this cycle treating the air as an ideal gas with (a) constant specific heats at room temperature and (b) variable specific heats.