At steady state, a heat pump driven by an electric motor maintains the interior of a building at Th=293 K. The rate of heat transfer, in kJ/h, from the building through its walls and roof is given by 8000 (Th-Tc), where Tc is the outdoor temperature. Plot the minimum theoretical electric power, in kW, required to drive the heat pump versus Tc ranging from 273 K to 293 K.