$4.$ Air enters a compressor operating at steady state at $\backslash (1\backslash$mathrm$\{$bar$\},300\backslash$mathrm$\{$~K$\}\backslash ),$ with a mass flow rate of $\backslash (4\backslash$mathrm$\{$~kg$\}/\backslash$mathrm$\{$s$\}\backslash )$ and exits at $6$ bar while undergoing a polytropic process with $\backslash ($ n$=1\mathrm{.}27\backslash ).$ Heat transfer occurs at a rate of $46\mathrm{.}95$ kJ per kg of air flowing in the compressor from the compressor to its surroundings. Assuming the ideal gas model for air and neglecting kinetic and potential energy effects, determine the power input, in kW$.($Answer:$-750$ kW$)$