1. The problem statement, all variables and given/known data A string wraps around a uniform cylinder of mass M, which rests on a fixed plane with angle θ. The string passes up over a massless pulley and is connected to a mass m. Assume that the cylinder rolls without slipping on the plane, and that the string is parallel to the plane. What is the acceleration of the mass m? 2. Relevant equations In the solucion, Morin claims that the masses acceleratins are not the same, and they are related by a2=2 a1, where a1 is the acceleratin for M, and a2 the acceleration for m 3. The attempt at a solution When solving the problem, I used the same value for both accelerations, that is, a1=a2=a, so my result was wrong. Why are the accelerations different, if the pulley is at rest? Where does the a2=2 a1 equation come from? Regrads.