Which statement about brake heat and stopping is true?

Which statement about brake heat and stopping is true?

• A. Brakes have less heat to absorb if the vehicle is heavy
• B. Heavier or faster vehicles require more heat to stop
• C. Heat does not affect braking performance
• D. Brakes cool instantly after use

Answer: (B)

When you brake, the system turns the vehicle’s kinetic energy into heat in the brake parts. The amount of heat that must be absorbed depends on how much kinetic energy you have to shed, which increases with both mass and speed. Heavier vehicles carry more energy, and faster vehicles have more energy at the same weight because energy grows with speed (actually with the square of velocity). So heavier or faster vehicles require more heat to stop. If that heat buildup is too great, braking power falls off—that’s brake fade. Brakes don’t cool instantly; they shed heat gradually as air flows over them and as you coast or drive, which is why managing speed and using engine braking helps keep temps in check. That’s why this statement is true: heavier or faster vehicles require more heat to stop.

When you brake, the system turns the vehicle’s kinetic energy into heat in the brake parts. The amount of heat that must be absorbed depends on how much kinetic energy you have to shed, which increases with both mass and speed. Heavier vehicles carry more energy, and faster vehicles have more energy at the same weight because energy grows with speed (actually with the square of velocity). So heavier or faster vehicles require more heat to stop. If that heat buildup is too great, braking power falls off—that’s brake fade. Brakes don’t cool instantly; they shed heat gradually as air flows over them and as you coast or drive, which is why managing speed and using engine braking helps keep temps in check. That’s why this statement is true: heavier or faster vehicles require more heat to stop.