1. The problem statement, all variables and given/known data Suppose a child driving a go-cart is traveling 4m/s when she crosses a line 4m from her starting point. She continues with a steady acceleration of 0.4m/s^2 , until she crosses a mark 40m from the starting point. How long does it take for her to go from the 4m mark to the 40m mark? what i did is this : a = 0.4m/s^2 Vi = 4m/s d = 40m - 4m = 36m i used this formula : Vf = Vi + a*t 0 = 4m/s + (0.4m/s^2)t -0.4m/s^2 = 4m/s t = -10s and this : d = Vi+Vt/2 * t 36m = (4m/s + 0)/2 * t 36m = 2m/s t divide both side by 2m/s t = 18s but the true answer is 6.7s anyone correct this ?