1. The problem statement, all variables and given/known data A cylinder of mass m is suspended through 2 strings wrapped around it at its ends, connected to the ceiling. Both strings have equal tension, and the cylinder rolls without slipping. r is the distance between the CM of the cylinder and each end. I is the moment of inertia of the cylinder. Find the tension T in the string and the speed of the cylinder as it falls through a distance h. 2. Relevant equations Equations for linear motion in vertical direction for center of mass of the cylinder, and that of rotational motion about the CM. 3. The attempt at a solution Linear: mg - 2T = ma Rotational: The solution says 2Tr = I*alpha (where alpha is angular acceleration). After this we simplify using angular acceleration= a/r, and solve the equations. I understand that part, but I don't get why 2Tr = Ia...both tensions are acting on the top of the cylinder, so the torques should be in opposite directions and cancel each other out, right? When I use torque = r x T, the directions come out of the page and into the page. But the equations say that both tensions contribute an equal torque in one direction. Why?