1. The problem statement, all variables and given/known data On a pulley with a very small radius and negligible inertia, that rotates without friction around its fixed horizontal axis, there is a chain of mass m and length l. The chain starts sliding from its equilibrium position. Let x be the distance between the ends of the chain. Express as a function of x: a) the acceleration of the chain. b) the force exerted by the chain on the pulley. 2. Relevant equations F = ma 3. The attempt at a solution a) The chain is composed of two parts: the part that starts sliding and keeps getting longer, of mass m1 and the part that keeps getting shorter, of mass m2. I think that on m1 act these forces: - m1g, its weight, positive - m2g, negative So the acceleration of m1 should be g(m1 - m2)/m1. This should also be the acceleration of m2. But I don't know how to express this acceleration in terms of x and l. As for the force acting on m2, it appears to me that it should also be m1g - m2g, which must be wrong, since the two bodies have the same acceleration and different masses.