(adsbygoogle = window.adsbygoogle || []).push({}); 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.

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# Homework Help: Rotational motion/Torque

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