1. The problem statement, all variables and given/known data A potter's wheel - A thick stone disk of radius 0.5m and mass 100kg is freely rotating at 50rev/min. The potter can stop the wheel in 6s by pressing a rag against the rim and exerting a radially inward force of 70N. Find the effective coefficient of kinetic friction between the wheel and the rag. 2. Relevant equations torque = RF Torque = I(moment of inertia) x radial acceleration 3. The attempt at a solution Sum of forces on the x axis: F(applied) - F(normal) = 0 F(applied) = F(normal) The froce of friction is on the y axis and is opposite to the direction the wheel turns, and F(friction) = (coefficient of friction)F(normal) Sum of forces on the y axis: I'm not sure what other force opposes the frictional force. Normally I would have thought F(friction) = ma, but it is not a particle that we are looking at, so i'm a little confused. And for the sum of the forces for torque, i know Torque = I(angular acceleration). Fir this i think I= 1/2 MR^2, and I can find angular acceleration with angular speed(final) = angular speed(initial) + angular acceleration X t. I'm also not sure what forces affect torque. Any help is appreciated.