Hello!
For this, first let's calculate time of stop:
t = (V - Vi) / a
Replacing:
t = (0 m/s - 18 m/s) / -5,4 m/s^2
Resolving:
t = -18 m/s / -5,4 m/s^2
t = 3,33 s + 0,25 s = 3,58 s
Now lets calculate distance traveled, with formula:
d = Vi*t + (a*t^2)/2
Replacing:
d = 18 m/s * 3,58 s + (-5,4 m/s^2 * (3,58 s)^2) /2
Resolving:
d = 64,44 m + (-34,604 m)
d = 29,83 m
Then, the vehicle will CRASH
