I am familiar with the basics concept of kinetic friction (such as pushing a box on a surface), but how do you calculate the friction torque caused by a bearing for example? In my college assignment, I have been told the bearings in a winding drum have a coefficient of friction of 0.04 (bearing size 200mm OD). The drum is 2.5m OD, and I know the load force on the outside of the drum (lets call it F). The torque caused by the load on its own is 1.25*F. Is the torque caused by the bearing friction therefore ((1.25*F)/0.1)*0.04? I hope this made some sense... Any help at all would be appreciated.