kinematics

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Speedy Sue driving at 30 m/s enters a one lane tunnel. She then bserves a slow moving van 155 m ahead traveling at 5 m/s. Sue applies her brakes but can only decelerate at 2.0 m/s^2 because the road is wet. Will there be collision? If yes, determine how far into the tunnel and at wht time the collison occurs. If no, determine the distance of closert apporach between Sue's car and the van.

Can someone help me? Kind of stuck..
 
You don't say what you want to use. I'll assume you know some calculus.
At time t Sue is going at
ds/dt = (30-2t).
s=int(30-2t)dt =
30t-t²
The truck is at 155+5t.
They will bump if
-t²+30t > 155+5t
The distance between them is
155+5t-(-t²+30t) =
t²-25t+155
 
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