1. The problem statement, all variables and given/known data Derive the equation for the linear acceleration of a falling mass m suspended by a string from the rim of a uniform disk of mass M and radius R that is free to rotate without friction about its principal axis. 2. Relevant equations a=rα linear acceleration = radius*angular acceleration Torque=inertia*angular acceleration 3. The attempt at a solution I don't really understand the question. If something is in free-fall, isn't its acceleration g? I just don't understand where the variables for the masses go. Any help is appreciated..