Question

An auto moving at a velocity of 20m/s can have a max deceleration of 10m/s^2. The driver of the auto sees a girl playing on the road at 20m and applies the full brakes, can he avoid the accident?

Answer 1

Given :

initial velocity of auto , u = 20 m/s

max deceleration , a = 10 m/$s^{2}$

distance of the girl = 20 m

To find :

Can the auto driver avoid the accident or not .

Solution :

when auto will stop , velocity will be zero .

final velocity , v = 0

let the distance after which auto will stop be s .

by 3rd equation of motion ,

         $v^{2}$ = $u^{2}$ + 2 * a * s

=>      0 = 20 * 20 + 2 * ( -10 ) * s

=>  400 = 20 * s

=> s = 20 m

As the distance after which auto will stop is equal to the distance of the girl , the auto driver can avoid the accident .