I am having problems with starting a certain problem. A train traveling at 297 km/h requires 1.45 km to come to an emergency stop. Find the braking acceleration, assuming constant acceleration. Now I am not given the acceration or time so this one is stumping me. I have tried several formulas including: deltaX = 1/2(a)(t)^2 + Vo(t) (v)^2 = (Vo)^2 + 2(a)(delta X) v = Vo +a(t) I cannot figure out how to get time or acceleration to solve for the other. The acceleration isn't due to gravity so it isn't (-9.8m/s^2) so I am at a loss for what equation to use. Should I solve for time first? If so, what is the equation I am missing? As far as I know, I am given Vo (297), Vfinal (0), delta Y (-297), delta X (1.45) and I have already tried converting km/h to m/s which the answer is supposed to be in. CONFUSED!!!!! Please help.