Electrical power companies sell electrical energy by the kilowatt-hour, where 1 kWh = 3.6x106 J.
Suppose that it costs $0.15 per kWh to run your
electric water heater. How much does it cost to heat
75 kg of water from 15°C to 43°C to fill a bathtub?

In a heat engine if 1000 j of heat enters the system and the piston does 500j of work, what is the final internal energy of the system if the inital energy was 2000 j1.write the equation2.list out your known variables 3. plug the numbers into the equations4.solve 5.write your solution statement that includes initial energy and final energy added.