So, I searched and found one almost identical to this, but no direction towards solution was posted, and I couldn't make sense of the formula in the original post. So... A red train traveling at 72km/h and a green train traveling at 144km/h are headed toward one another along a straight level track. When they are 950m apart, each engineer sees the other's train and applies the brakes. The brakes slow each train at the rate of 1m/s^2. a) Is there a collision? b) If so, what is the speed of each train at impact? So, I know that they collide, and that the red train has stopped, but I'm not sure where they collide. I know that the red train stops after 20 seconds, and that the green train would stop after 40 seconds if it didn't collide with the red one first, but I'm having a huge mental block and can't remember or seem to find the formulas that would help me out here. The book I'm using doesn't seem to have them either. Can anyone help me out here? I feel really stupid because I *KNOW* this is relatively simple, I just can't wrap my brain around it right now.