1. The problem statement, all variables and given/known data at the instant the traffic light turns green, s starts from rest and accels at a_s. at the same time k passes s with constant velocity v_k. given a_s, v_k, find distance before the cross again time it takes to do so velocity of s at this point plot the position as a function of time for both. take x=0 at the intersection <- no idea what last sentence means. 2. Relevant equations v_s = a_s + t d = 1/2 a_s * t^2 v_s^2 = 2a_s*d d= v_k * t 3. The attempt at a solution t = sqrt(2*v_k/a_s) d = v_k * sqrt(2d/a_s) v_s = a_s*sqrt(2d/a_s) as for this plotting, does this mean I "start" the graph at their intersection? which one?