Kayleigh is driving a car at 80k/h when she spots a sign that read "bridge out ahead." it takes her 1.0 s to react and begin braking. the car slows down at a rate of 3.0 m/s^2. luckily, she stops 5.00 meters short of the washed-out bridge
a)how much time was required to stop the car once the brakes were applied
b)how far was Kayleigh from the bridge when she first noticed the sign?
80 km/hr = 22.22 m/s
from the time she started braking, her velocity is
v = 22.2 - 3t
So, it takes her 7.4s to stop
Now you can figure the distance in the usual way. Be sure to add the 22.2m gone before she started to brake.