1. The problem statement, all variables and given/known data A tractor named A is used to lift a bale B with a system of pulleys. The tractor has an unknown speed called VA : find the expression of the bale's vertical speed VB in function of x (distance from the tractor to the pulley). The diameter of both pulleys can be neglected. 2. Relevant equations I call T the tension in the rope, N the reaction of the ground and W=mg the weight, mA the tractor's mass and mB the bale's mass, aA the tractor's acceleration and aB the bale's acceleration. In A, I have : horizontally -T*(x/l) = mA * aA vertically :N - mA*g + N*(h/l) = 0 In B : T - mB*g = mB*aB 3. The attempt at a solution I've tried to put the problem into some equations, but I don't see how I can switch from accelerations to speed...moreover, I don't have any numeric data, so any piece of information is welcome! Thanks in advance!