Question

A potter's wheel—a thick stone disk of radius 0.500 m and mass 125 kg—is freely rotating at 50.0 rev/min. The potter can stop the wheel in 6.00 s by pressing a wet rag against the rim and exerting a radially inward force of 72.0 N. Find the effective coefficient of kinetic friction between the wheel and rag.

Answer 1

Initial angular velocity of the wheel,

To convert rev/min to rad/s. Multiply by

Final angular velocity,

Time,

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Radius of the disk,

Mass of the disk,

Radial inward force,

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First, find angular deceleration

Use formula

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Consider the disk

Net Torque = Moment of inertia*Angular acceleration

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Frictional force = Coefficient of friction* Radial force

Moment of inertia of the solid disk,

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Cancel the negative sign.

ANSWER:

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