Brakes transform the motion of the vehicle into which kind of energy?
- Electrical energy.
- Potential energy.
- Mechanical energy.
- Heat energy. ✓
Answer: D. Heat energy.
Brakes turn the vehicle's motion into heat energy.
Why this is the answer
The handbook uses a rollerblade pad skidding on pavement as its example: friction between the pad and the ground makes both get hot, because motion energy becomes heat. It says vehicle brakes work the same way — linings rubbing on a drum, or pads on a rotor, create friction that converts the energy of motion into heat, which is absorbed by the drums or rotors and released into the air. The stated principle is simply that friction converts motion energy to heat energy.
Why the other answers are wrong
- A. Electrical energy. — The passages describe friction turning motion into heat at the drum or rotor, not into electrical energy.
- B. Potential energy. — Potential energy is not what the passages name; they say the energy of motion becomes heat through friction.
- C. Mechanical energy. — Mechanical energy is the energy of motion the vehicle already has, so it is what the brakes convert from, not into.
Remember it
Think of the rollerblade pad and the hot pavement: rubbing away motion always leaves heat behind.