1. The problem statement, all variables and given/known data http://img511.imageshack.us/img511/8721/problem1ldc0.jpg [Broken] 2. Relevant equations They are listed in the image above, but it`s all rooted in the basic Tension equation: F-Ft=ma 3. The attempt at a solution This is a different question I am asking. The problem IS solved as you can see. But I am having trouble understanding the logic behind it. The writers say that mass 1 has twice the acceleration as mass 2. They totally lost me there. Why is that the case? And how do I interpret it from the image? And then they say that when the pulley moves a distance d, m1 moves 2d. Once again, I`m clueless as to why that is. And when they say the pulley moves, they mean the pulley is moving rather than rotating, right? But either way, I lost the point. Why will m1 move distance of 2d? Wouldn`t that entail it going ahead of the pulley, or will the rope pulling it make it come in contact with the pulley? Then they say, the tension in Ft1 is half that of Ft2. Why?? How did they arrive at that observation? I cannot interpret the reason from regarding the image alone. Why would the total force on the pulley being zero make Ft1 have less tension?? Somebody please help me.