Hello. I've been stuck on this question for ages, and was hoping someone could help me with it. 1. The problem statement, all variables and given/known data A stone is projected vertically upwards with a speed of 6m/s, and one second later a second stone is projected vertically upwards from the same point with the same speed. Find where the two stones meet. 2. Relevant equations http://img193.imageshack.us/img193/4696/4bes.jpg [Broken] 3. The attempt at a solution http://img195.imageshack.us/img195/908/4bp1.jpg [Broken] http://img140.imageshack.us/img140/1691/4bp2.jpg [Broken] http://img193.imageshack.us/img193/4383/4bp3.jpg [Broken] http://img148.imageshack.us/img148/6464/4bp4.jpg [Broken] As far as I can tell, I've worked out how high above the projection point the first stone is, when the second stone is launched. I also worked out that the first stone is travelling at 4m/s at 1m above the ground after 1 second. I tried doing this through trial and error, and came up with the collision at 0.15m above the projection point, 0.17 seconds after the second stone is launched, but I don't think that is the method I'm supposed to be using here. :shy: I don't think I've ever done a question like this before, so I would really appreciate any help. Thanks.