Hello PF! 1. The problem statement, all variables and given/known data A string is wrapped around the small cylinder as shown. You pull with a force F (and the cylinder does not slide). Calculate the acceleration of the cylinder CM (including direction). Here r = 3 cm, R = 5 cm, F = 0.1 N, and m = 1kg. [Make sure to define one direction of rotation (CW or CCW) as positive, just like you define one direction of X as positive. If you use a relationship like v=R or a=R you need to make sure that your definitions are consistent] Correct solution: 0.0267 m/s^2 2. Relevant equations Sum of the torques = Iα Moment of inertia of a solid cylinder = 1/2MR^2 3. The attempt at a solution Let counter clockwise torques be positive for the purposes of this solution. I started by calculating the torques about point C, where C is the center of mass of the cylinder. Since the cylinder is rolling without slipping, the force due to static friction on the cylinder must be equal and opposite in magnitude to the applied force, F. Ʃt = R*Fs - r*F ƩF = Fs - F = 0 Iα = R*F - r*F ac/R = (R*F - r*F)/I ac = 2(R*F-r*F)/(MR) ac = 0.08 m/s^2 Is it wrong to equate Fs to F in this case? Or is there another factor that I'm not considering?