Question

a car moving with of 50km/hr can be stooped by brakes after at least 6m. if the same car is moving at speed of 100km/hr the minimum stopping distance is

Answer 1

follow simple approach v^2-u^2=2as where v is final velocity which is gonna be zero in this case as the car is gonna stop,a is the negative acceleration or you can call deacceleration and s is the distance covered.

now as per the equation u^2 is directly proportional to distance provided (negative) acceleration remains same. so if speed become twice ,distance will become four folds ,that is 6*4 =24m

or