13. Air enters a compressor operating at steady state at 15 lbf/in., 60F, with a volumetric flow rate of 5000 ft/min. The compression occurs in two stages, with each stage being a polytropic process with n= 1.3. The air is cooled to 100F between the stages by an intercooler operating at 40 lbf/in.2 Air exits the compressor at 120 lbf/in.2 Determine, in Btu/min: (a) The power and heat transfer rate for each compressor stage. (b) The heat transfer rate for the intercooler.