[SOLVED] Constant Acceleration 1. The problem statement, all variables and given/known data At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.1 m/s^2. At the same instant a truck is 10.2 m down the road and traveling with a constant speed of 8.5 m/s. (a) How far beyond the traffic signal will the automobile overtake the truck? (b) How fast will the automobile be traveling at that instant? 2. Relevant equations 3. The attempt at a solution s(t) = 1/2 a * t^2 + v0 * t + s0 a = acceleration v0 = initial speed s0 = initial position Being for the truck a = 0 m/s^2 v0 = 8.5 m/s s0 = 10.2 m and being for the car a = 2.1 m/s^2 v0 = 0 m/s s0 = 0 m the equation will be: 8.5 m/s * t + 10.2 m = (There is a 1/2 here right?) (1/2)2.1 m/s^2 * t^2 Solving this I get 9.156s which is apparently incorrect.