1. ## Friction

The skid mark left on the road by a vehicle which had its wheels locked is 120 m . The coefficient of kinetic friction between the road and the tyres is 0.75 . Assuming that the kinetic energy of the vehicle equals the work done against friction , derive the relationship between the speed , v of the vehicle before the wheels aRe locked and the length L of the skid mark on the road .

2. Originally Posted by thereddevils
The skid mark left on the road by a vehicle which had its wheels locked is 120 m . The coefficient of kinetic friction between the road and the tyres is 0.75 . Assuming that the kinetic energy of the vehicle equals the work done against friction , derive the relationship between the speed , v of the vehicle before the wheels aRe locked and the length L of the skid mark on the road .
Kinetic energy dissipated= work done by friction

Kinetic energy dissipated= $\frac{1}{2}mv^2$
where m is the mass of the vehicle, and it is assumed that the vehicle stops after skid.

Work done by friction= $\mu mgL$
where $\mu=0.75$(given, coefficient of friction), g is acc. due to gravity.