Question

A driver sees a boy and his dog in the road, and it takes the driver 0.50 seconds to put on the brakes. if the car travels 14 meters during that time, what is its velocity.

Answer 1

Given ,

v=0 m/s                t=1/2 seconds                   s=14 m                  a= deceleration

v = u+at

0 = u+a(1/2)

a = -2u m/s²

We know that ;

s = ut+1/2(a)t²

14 = u/2-u/4 = u/4

u = 56 m/s