1. The problem statement, all variables and given/known data A train pulls away from a station with constant acceleration of .4 m/s^2. A passenger arrives at a point next to the track 6.0s after the end of the train has passed the very same point. What is the slowest constant speed at which she can run and still catch the train? 2. Relevant equations [tex]\Delta[/tex]x = v0t + a/2*t2 V2f=V2i+ 2a*[tex]\Delta[/tex]x 3. The attempt at a solution I can find the position functions of both objects, but I can't rearrange the formulas just right where I'll end up with just one unknown. i.e. Xpassenger = v0t Xtrain = 7.2 + 2.4*t + .2*t2 I know their positions have to be the same and I know their velocities have to be the same at that point (I picture it as a line touching the tip of a quadratic, like a derivative). Since it's asking for a minimum, I'm also unsure of how to apply calculus. i.e. What am I taking the minimum of?