kinetic Vs Static coefficient of friction?

Question

Can anyone help me with this quesion?
Which one is higher and which one applies during a skidding car?

Answer 1

Static coefficient of friction is usually larger. When your tires are rolling along normally, you are dealing with static (or rolling) friction.

When you start to skid, the wheels are not moving, so they are sliding across the road - that's where you would use the coefficient of kinetic (or sliding) friction.

Answer 2

For the skidding car, go back and look at the definitions of static and kinetic friction. The word "kinetic" means "related to motion", as in "kinetic energy." Maybe it will help to remember that "cinema" is a motion picture?

As for "which is higher", the static coefficient is generally larger than the kinetic coefficient, but there is no underlying fundamental physical law that requires this to be true. Still, some books will tell you that the static coefficient is ALWAYS larger, as if there were such a law.