Question

John is driving at 25m/s. When he brakes, he accelerates at the rate of -5.0m/s^2.

How much time did it take him to stop?
How far does it take him to stop?

Answer 1

v = Vi + a t
at end v = 0 so
0 = 25 - 5 t
t = 5 seconds

d = vi t + .5 a t^2
d = 25(5) - 2.5 (25)
d = 125 - 62.5
d = 62.5