1. The problem statement, all variables and given/known data A uniform cylinder, of radius 2a and moment of inertia $2Ma^2$ is free to rotate about its horizontal axis. A light, inextenzible string is wound round the cylinder and a particle of mass m is suspended on its free end. If the system is released from rest, find the acceleration of the particle. 2. Relevant equations Torque(C)=Moment of inertia(I) x (angular accleration)$\alpha$. 3. The attempt at a solution Resolving the tension in the string, we get T=mg-2ma(alpha) Which gives upon calculating the angular acceleration (given that I=2Ma^2) alpha=(mg)/(2am+Ma) which is somehow incorrect. Can someone correct my error?