A car moving at 50 km/h skids 15 m with locked brakes. How far will the car skid with locked brakes at 150 km/h

Kinetic energy = (1/2 m) x (speed) ²

A car moving 3 times as fast has 9 times as much kinetic energy.

If the force of friction between the tires and the ground

is the same at every speed, then the car has to go 9 times

as far to burn off the increased kinetic energy.

9 x 15m = 135 meters

with 50 km/h = 15m skid

so, 150 km/h = 45m skid

multiply sides by 3, make them proportional to each other!