Potters wheel coefficient of kinetic friction

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SUMMARY

The discussion focuses on calculating the effective coefficient of kinetic friction between a potter's wheel and a wet rag. The wheel has a radius of 0.49 m and a moment of inertia of 10.6 kg·m², rotating at 52 revolutions per minute. To stop the wheel in 5.5 seconds, a radially inward force of 68 N is applied. The solution involves determining angular acceleration, total torque, and subsequently calculating the friction coefficient using the relationship μN.

PREREQUISITES
  • Understanding of moment of inertia and its formula (I = 0.5mr²)
  • Knowledge of angular acceleration and its calculation
  • Familiarity with torque and its relationship to force
  • Concept of coefficient of kinetic friction (μ) and normal force (N)
NEXT STEPS
  • Calculate angular acceleration from initial and final speeds using kinematic equations
  • Determine total torque using the moment of inertia and angular acceleration
  • Apply the formula for coefficient of kinetic friction (μ = τ/N) to find the effective friction
  • Explore real-world applications of friction in rotational dynamics
USEFUL FOR

Physics students, mechanical engineers, and anyone interested in understanding the dynamics of rotational motion and frictional forces.

arogers5
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Homework Statement



A potter's wheel having a radius 0.49 m and a moment of inertia of 10.6 kg · m2 is rotating freely at 52 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 68 N. Find the effective coefficient of kinetic friction between the wheel and the wet rag.



Homework Equations



I = .5mr^2





The Attempt at a Solution



I wasnt sure where to start. I know how to solve for the mass of the wheel, I know the moment of inertia formula and I know that the coefficient of kinetic friction is equal to μN. I drew a picture of the situation but am not sure how the moment of inertia and the decelleration are going to relate to the force that is applied.
 
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welcome to pf!

hi arogers5! welcome to pf! :smile:

first do the geometry, then the physics

the geometry is the angular acceleration: find it from the given initial and final speeds, and the time

then use the moment of inertia to find the total torque

then subtract to find the friction :wink:
 

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