1. The problem statement, all variables and given/known data Two cyllinders of equal size and of mass M (one hollow, one solid) are connected along their common axis by a light rod and placed on an inclined plane with an incline of α (both cylinders are on the same height initially). The system of cylinders then begins to roll down the inclined plane without skidding. Find the tension in the rod. Given variables: M, α, g (gravitational acceleration) 2. The attempt at a solution and the problems I'm facing My biggest problem is imagining what causes the tension in the first place. My guess is, due to the cylinders having equal mass, but different moments of inertia, their rate of descent would be differ if they weren't connected by the rod (the hollow one would roll slower because of a larger moment of inertia). So since they are connected, the difference of their altitudes creates the tension, which makes the system roll down in a curved trajectory. Is that where tension arises from? Cause otherwise (if the cylinders were identical) I would think that the tension would be equal to 0.