Question

Five Part Question: One gallon of gasoline releases approximately 120 million Joules when it is burned. A car engine operates at an efficiency of around 25%.

1. Of the energy available in a gallon of gas, how much energy can be used to do useful work in moving the car?

2. How much heat per gallon is released into the environment via the exhaust and radiator?

3. If the car is moving at a constant speed, why is it still burning gas? What as the energy output of the engine used for at a constant speed?

4. Would you expect the efficiency of the engine to be better on a hot or cold day? Note that this is a complex scenario and there's no clear correct answer, and in fact you could argue either way.

5. Is the burning of gasoline reversible? Explain.

Answer 1