a change in phase thermal expansion an increase in entropy mechanical advantage
I gave my students this multiple choice question: When Dennis operates his lawnmower, he notices the engine makes a lot of noise. He also notices that the engine gets very hot. Which best describes the heat and noise generated from the lawnmower?

Only one answer is correct among these 4 choices:
- a change in phase
- thermal expansion
- an increase in entropy
- mechanical advantage

Could you tell me which one is correct?

an increase in entropy