The speed limit in a school zone is 40Km/
h. A driver traveling at this speed sees a
child run into the road 13m ahead of his
car. He applies the breaks, and the car
decelerates at a uniform rate of 0.8m/s².
If the driver's reaction time is 0.25
seconds, what distance will the car travel
before coming to rest?
how long does it take to stop?
40km/hr = 11.11 m/s
v = 11.11 - 0.8t
find t when v=0
Now,
s = 11.11(t+0.25) - 0.4t^2