Acertain car takes 30m to stop when it is traveling at 25m/s. if a pedestrian is 28m in front of this car when the driver starts braking (starting at 25m/s), how long does the pedestrian have to get out of the way?

It take 1.78033 second get away

Explanation:

We have given that a car takes 30 m to stop when its speed is 25 m/sec

As the car stops its final speed v = 0 m/sec

Initial speed u = 25 m/sec

Distance s = 30 m

From third law of motion

So

Now in second case distance s = 28 m

So

v = 6.4549 m/sec

Now from first equation of motion v=u+at

So

t = 1.78033 sec