1. The problem statement, all variables and given/known data A bucket of water is raised up out of a well with a device of the rope, and pulleys as shown in figure. The bucket is hanging from the the lower hook and the upper hook is attached to a fixed cross bar of the well. If the mass of the bucket and the water together is m, and the man pulls the rope with a force F, how large is the span's acceleration up? The mass of ropes and pulleys can be neglected, as well as frictional forces. http://bayimg.com/daOdPAAde [Broken] Answer: (3F/m)-g 2. Relevant equations F=mg and maybe F=ma 3. The attempt at a solution Due to gravity there is a force downward. Since the mass of the bucket and the water together is m, the downward force is mg. From figure I see that the device is constructed so that the cable runs three times between the bucket and the hook before I pull it. Therefore the force required for the bucket to move upwards is F=mg/3≥. From here I am stuck. I know that F=ma and therefore a=F/m. However, if I insert F=mg/3 and m=mg, I get the wrong answer.