Heat engines and ecology
Answers are for parents and teachers.
1
Efficiency 35%, Q₁ = 4000 J. What is the useful work (J)?
1400
2
An engine does 800 J of work taking 2000 J of heat. What is the efficiency (%)?
40
3
Burning fuel gives 90 MJ of heat, efficiency 30%. How many MJ go to the cooler?
63
4
Name two ways to reduce air pollution in cities.
Catalytic filters, electric vehicles or public transport.
5
Why does a car engine need a cooling system?
Excess heat must be removed so that the engine does not overheat and its parts are not damaged.