I have two hollow cylinders of different sizes. The smaller cylinder is inside the larger cylinder but NOT concentrically. The OD of the smaller cylinder contacts the ID of the larger cylinder at the 6 o'clock position. Both cylinders rotate but in opposite directions. An actuator pushes the larger cylinder upwards applying a normal force to the smaller cylinder. I know the torque being applied to each cylinder, the constant rotational speeds of each cylinder and the force being applied to the actuator. I also know the weights of everything. How would i find the coefficient of friction of the two materials that are rubbing together?