stopping the car

[denian]

can someone explain to me the difference btw
(a) apply the brakes just hard enough

and

(b) brakes are applied too hard??

[Doc Al]

Apply the brakes too hard and the tires will slip on the road; apply them just right, and they won't slip. The only force stopping the car is the friction of the road on the tires: you want the friction to be as great as possible. If the tires slip you have kinetic friction, which is weaker than static friction.

[denian]

thank you doc al.