A driver traveling at 44.0km/h in a school zone can brake to an emergency stop i

Question

A driver traveling at 44.0km/h in a school zone can brake to an emergency stop in 3.20m . What would be the braking distance if the car were traveling at 58.0km/h?

The answer is asking for m, so you have to convert 44.0km/h and 58.0k/h into m/s, which I did, which are 12.2m/s and 16.1m/s.

After that is when I get confused, I do not understand how to find the distance and my physics teacher did not provide any insight on how to solve this. It is probably extremely easy, I just do not know how to figure it out. For this unit, we are given 3 equations, which I have tried to incorporate them to solve it but still cannot figure it out.

x = x0 + v0t +1/2(a)(t2)

v = v0 + at

v2 - v20 = 2a(x-x0)

Thanks!

Explanation / Answer

44 km/h = 12.22 m/s

58 km/h = 16.11 m/s

use v^2 = v0^2 + 2 a x

stops when v = 0

0 = 12.22^2 +2*a*3.2

a=-23.33 m/s^2

now at greater speed

use v^2 = v0^2 + 2 ax again

0 = 16.11^2 +2*-23.33*x

x= 5.56 m

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