A car having initial speed of 50kmh−1 is brought to rest in atleast 6 m by applying brakes. What would the minimum stopping distance be if the same car was moving at a speed of 100kmh−1 ?

Stopping distance, ds=u22a Where u is the initial speed of the car. As the stopping distance is proportional to square of the initial velocity.Doubling the initial velocity increases the stopping distance by a factor of 4.