Question

2.1.4 quiz: conservation of energy
a car engine uses the combustion of fuel to move a system of gears that move its wheels. not all of the fuels energy is transferred to the wheels. which two options describe what happens to the rest of the energy?

a. some energy is lost because it is absorbed by the driver.

b. some energy is lost because it is transformed into chemical energy.

c. some energy is lost because of the friction between the gears.

d. some energy is lost because it is transformed into thermal energy.

e. some energy is lost because it is transformed into potential energy.

Explanation:

• Option A: Driver doesn't absorb significant engine energy, so A is wrong.
• Option B: Fuel combustion is chemical to other forms; energy isn't lost by turning back to chemical, so B is wrong.
• Option C: Friction between gears converts mechanical energy to thermal (heat), so energy is "lost" (transferred) here, C is correct.
• Option D: Engine operations (including friction, inefficiencies) transform energy to thermal (heat), which is a common energy loss in engines, D is correct.
• Option E: Car's motion is kinetic; potential energy isn't a main loss here, so E is wrong.

Answer:

C. Some energy is lost because of the friction between the gears.
D. Some energy is lost because it is transformed into thermal energy.