Question

Reaction time of a driver is 0.5s. The vehicle can gain a deceleration of 5ms^-2 by applying brakes. What is the minimum distance that the driver should see a danger in order to avoid it from an accident by applying brakes

Answer 1

$S=vt-1/2 at^2$

V= velocity

So in the question, there is no velocity (V). Therefore $v=0$.

And we are using the minus($-$) because it is decelerating. 

$t=0.5$

$a=5$

Therefore $S=0×0.5-1/2 (5) (0.5)^2$ $=-0.626m$