1. The problem statement, all variables and given/known data The problems asks: According to the above sketch, find accelartion (a1) of mass1? Note that the cables and pulleys are ideal (massless and frictionless). Everything started at rest untill the pulleys lock were realsed. m1, m2, m3 have all different masses. 2. Relevant equations a1 = a2 + a3 F = ma 3. The attempt at a solution Here's what i have set up so far, correct me if i am wrong: Known: m1, m2, m3, g Unknown: a1, a2, a3, T1, T2, T3 (T=Tension, a= acceleration, m=mass) System 1: m1 x: 0 y: T1 + W = m1a1 System 2: m2 x: 0 y: T2 + W = m2a2 System 3: m3 x: 0 y: T3 + W = m3a3 a1 =a2 + a3 I don't know what to do from here, i guess its because my set up is wrong. I was told by a friend that just 2 systems are required, and that system 2 is m2 and m3 combined. Thus Tension 1 would be T1 = T2+3. But i am not sure if thats correct either. Any help solving or setting up the problem would be greatly appreciated. Thanks in advance. Thamer H.