1. The problem statement, all variables and given/known data Here is the diagram and I need to find a relationship between the acceleration in block A and the acceleration in block B. http://dl.dropbox.com/u/64325990/HW%20Pictures/datum2.PNG [Broken] 3. The attempt at a solution Here is my diagram, which is wrong: http://dl.dropbox.com/u/64325990/HW%20Pictures/Photo%202012-04-08%209%2039%2025%20PM.jpg [Broken] It is wrong in that there shouldn't be a negative sign in front of aB. Instead 3aA=2aB is the correct answer. However I do not know how to derive that answer and where to put my datum. I need help with the diagram, thanks!