A power plant burns 1000 kg of coal per hour to produce a net output of 500 kW of electrical power. Assuming each kg of coal produces 6 MJ of energy determine: The rate of heat rejection to the sink. The overall thermal efficiency of the power plant. A heat engine accepts 700 kJ of heat from a thermal source and rejects 250 kJ of that heat to a thermal sink. What is the work output of the heat engine? What is its thermal efficiency?