Find time given velocity and distance

[Calhoun295]

Homework Statement

A certain vehicle requires a distance of 29 m to stop when it is traveling at 28 m/s.
(a) What magnitude of acceleration is produced by braking under these conditions?
(b) If a jaywalker is 27 m in front of the vehicle when the driver first applies the brakes, how much time does the pedestrian have to get out of the way?

Homework Equations

v=v_o + at
x - x_o = v_ot + $$\frac{1}{2}$$at²
v² = v_o² + 2a(x - x_o)

are the given equations for what we're learning.

The Attempt at a Solution

(a) 13.52m/s²
(b) is what I cannot find

 

[Doc Al]

I'll rephrase the question: How long does it take the vehicle to cover 27 m?