A 1000 kg car traveling at a speed of 27 ms skids to a halt

A 1000 kg car traveling at a speed of 27 m/s skids to a halt on wet concrete where mu_k = 0 60. How long are the skid mark? Express your answer using two significant figures.

Solution

We know that when the car skids the maximum retarding force is the kinetic friction.

Hence it will be

Fk = mg * coefficient of kinetic friction

Fk = 1000 * 9.8 * .6 = 5880 N

Hence the accelration in the car will be

a = 5880 / 1000 = 5.88 m/s^2

Using newton\'s equations

V^2 - U^2 = 2 a L

Hence

L = U^2/2a

L = 61. 98 meters