1. The problem statement, all variables and given/known data This is a "DOE" (Design of Experiment) problem. Basically, the construction is fairly simple. 3 pulleys, 2 on either side, and a free pulley with a weight suspended on it in the middle. Picture is available (don't mind my crappy paint skills, rope lengths are all parallel). I basically need to compare theoretical velocity of C after falling 5cm and after falling 85cm to my actual measured velocities. However, to be honest my experimental values are all sorts of messed up, and I'm simply not sure if my math is anywhere near right. m1 = .270kg m2 = .522kg m3 = .300kg 2. Relevant equations F(net) = ma xf = 1/2at^2 + Vot + xi (dx/dt and dv/dt respectfully) 3. The attempt at a solution First I set up my three equations. m1g - T1 = m1a T1 = m1g - m1a Eq1 2T2 - m2g = m2a T2= 1/2(m2g + m2a) Eq2 m3g - T3 = m3a T3 = m3g - m3a Eq3 So, Fnet = ma should be T1 + T3 - T2 = ma (what is m? The mass sum of the system?) Plug in. m1g - m1a + m3g - m3a - 1/2m2g - 1/2m2a = ma m1g + m3g - 1/2m2g = a(m + m1 + m3 + 1/2m2) Isolate for a = (g[m1 + m3 - 1/2m2]) / (m + m1 + m3 + 1/2m2) If I plug in what I *think* m is supposed to equal (1.092), I get a = 1.923m/s Integrate a Vf = 1.923t + Vo (Vo is 0) Integrate vf xf = .9615t^2 + xo (Xo is also 0) Plug in .85m for Xf (furthest displacement of weight 3) t = .94s Vf = 1.923(.94) Vf = 1.808 m/s at .85m ...not even close am I?