1. The problem statement, all variables and given/known data I am trying to find the time a collision occurs of car 1 that is travelling 31m/s and can accelerate at -1.8m/s and car 2 that is traveling at a constant velocity of 6m/s. 2. Relevant equations v(final)^2=v(initial)+ 2a(x(final) - x(initial)) v(final) = v(initial) + at x(final) = x(initial) + v(initial)t + .2at^2 3. The attempt at a solution I found change in velocity of car 1 over the 30 meter distance. v(final)^2 = 31^2 - 2(-1.8)(-30) = 28,837 28.837 = 31 + (-1.8)t ............t = 0.996 the distance car 2 traveled over the 0.996s is 5.976m so adding the distance car 2 traveled plus the distance car 1 is initially from car 2... v(final)^2 = 31^2 - 2(-1.8)(-35.976) = 28.835 28.835 = 31 + (-1.8)t..................t =1.204s Which 1.204 seconds turned out to be the wrong answer. Would I have to find the relative velocity between the cars over the 30 meters? Would the relative velocity be the average over the 30m? I am not sure what else to look at. Thanks for the help!