A potter's wheel having a radius 0.46 m and a moment of inertia 11.1 kg·m2 is rotating freely at 53 rev/min. T

Question

A potter's wheel having a radius 0.46 m and a moment of inertia 11.1 kg·m2 is rotating freely at 53 rev/min. The potter can stop the wheel in 5.5 s by pressing a wet rag against the rim and exerting a radially inward force of 69 N. Find the effective coefficient of kinetic friction between the wheel and the wet rag.

Answer 1

α = ∆ω/∆t = 53(2π/60)/5.5 = 1.009 rad/sec²

Q = I*α = 11.2 N∙m

Ff = µFn = Q/r = 24.35 N

µ = 24.35/Fn = .353