Question

By law, the brakes on every vehicle other than a motorcycle must___.

1) Not lock under any condition.
2) Consist of a good foot brake in an emergency or parking brake.
3) Consist of a good parking brake that is capable of stopping the vehicle within legal limits.

Answer 1

When braking, the transition from static to kinetic friction explains the need to let up slightly on the brake pedal to avoid stopping with a bump.

Step-by-step explanation:

When you learn to drive, you discover that you need to let up slightly on the brake pedal as you come to a stop or the car will stop with a bump. This can be explained in terms of the relationship between static and kinetic friction.

When the brakes are initially applied, there is static friction between the brake pads and the rotor or drum. Static friction is the friction between two surfaces that are not moving relative to each other. As the car slows down and the speed decreases, the static friction starts to decrease, and the kinetic friction between the brake pads and the rotor or drum comes into play. Kinetic friction is the friction between two surfaces that are in motion relative to each other.

The relationship between static and kinetic friction explains why you need to let up slightly on the brake pedal as you come to a stop. If you continue to apply the same amount of pressure on the brake pedal, the brakes will lock up and the car will stop with a bump. By releasing some pressure on the brake pedal, you allow the brake pads and the rotor or drum to transition from static friction to kinetic friction smoothly, resulting in a smoother and more controlled stop.