1. The problem statement, all variables and given/known data A ball is thrown vertically upwards at 5 m / s from a roof top of 100m. The ball B is thrown down from the same point 2s later at 20 m / s. Where and when will they meet. 2. Relevant equations S = So + ut + 1/2at^2 3. The attempt at a solution well at first I separated the fact that while ball B falls at say t seconds, ball A's time is given by t+2 (due to it being thrown 2 seconds prior to ball B). given what's given above (the velocity and height)...I wrote down the following equations to find TIME, where lower a and b denote ball A and B: Sa = Soa + ua(t+2) + 1/2a(t+2)^2 Sb = Sob + ubt + 1/2at^2 but i tried equalizing the above two equations with all the proper variables replaced by the values provided in the problem, but unfortunately i don't get the right answer. I'm lost, I'm not even sure if I tackled the problem correctly.