Final answer:
When you learn to drive, letting up slightly on the brake pedal as you come to a stop is necessary to avoid a jer`ky stop.
Step-by-step explanation:
Static friction is the force that acts between two surfaces that are not sliding against each other. When you press the brake pedal, static friction is responsible for stopping the car. However, as the car slows down, static friction decreases and kinetic friction takes over.
Kinetic friction is the force that opposes the motion of two surfaces sliding against each other. When the car is moving, the brakes create kinetic friction to slow down the car. If you continue to press the brake pedal with the same force, it can cause a je`rky stop because the brakes are producing more force than necessary to overcome the kinetic friction.
By letting up slightly on the brake pedal, you decrease the force applied by the brakes, allowing the kinetic friction to match the slowing force of the car. This results in a smoother stop without a je`rk.