How far will a 1000kg car skid with locked brakes if it is traveling at 120km/HR if when braked(locked) while moving at 40km/HR comes to a stop after 20.0 meters(g~10m/s)?

M-when a car skids to a stop, the work done by friction upon the car is equal to the change in kinetic energy of the car. work is directly proportional to the displacement of the car (skidding distance) and the kinetic energy is directly related to the square of the speed (ke=0.5*m*v2). for this reason, the skidding distance is directly proportional to the square of the speed. so if the speed is tripled from 40 km/hr to 120 km/hr, then the stopping distance is increased by a factor of 9 (from 20 m to 9*20 m; or 180 m).