Thank you Mr. Bridge, for your reply. I am still confused however, as towhat the force on a differential element would be. The friction force would be μ N=μ m g(or would it be μ g dm?) The friction force would always act perpendicular to position, so torque would be upward with magnitude equal...
If I have a spinning circular disc of uniform density, how would I find the torque generated by friction, if the disc is lying flat against a table with coefficient of friction μ? τ=Fxr, but what is F, and what is r in this case?