When you see a traffic light turn red, you apply the brakes until you come to a stop. Suppose your initial speed was 12.9 m/s, and you come to rest in 35.0 m. How much time does this take? Assume constant deceleration.

What equation do I use to solve this problem? You can show me some steps to solve the problem. Thanks

1 answer

V^2 = Vo + 2ad.
V = 0.
Vo = 12.9 m/s.
d = 35 m.
a = ?. Solve for a. It will be negative.

V = Vo + at.
V = 0.
Vo = 12.9 m/s.
a = Previous calculated value.
t = ?.