Figure 2-24 shows a red car and a green car that move toward each other. Figure 2-25 is a graph of their motion, showing the positions xg0 = 270 m and xr0 = -35 m at time t = 0. The green car has a constant speed of -20 m/s and the red car begins from rest. What is the acceleration magnitude of the red car? The graph of their motion shows the two cars intersect their position at t = 12 seconds. I started out by interpreting the labels and information. Xo (g) : 270m Xo (r) : -35m (Constant) V (g) : -20m/s Vo (r) : 0 m/s. t = 12 seconds. 1. I used the formula X = Xo + ( V - Vo/ 2 )t to get the position at which the cars meet. X = 270 + (-20/2)12 X = 150m, Then I used the formula X = Xo + Vot + 1/2at^2 to get the acceleration of the red car. 150 = -35 + 0 (12) + 1/2a(12)^2. This yielded a = 1.68 m/s*s The answer is supposed to be a= 0.9m/s*s. Where did I go wrong? Was my interpretation of the data incorrect? Or just the way I plugged in the data?