Potters wheel coefficient of kinetic friction

arogers5
Messages
1
Reaction score
0

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.
 
Physics news on Phys.org
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:
 
Thread 'Need help understanding this figure on energy levels'

Thread 'Need help understanding this figure on energy levels'

This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
View full post »
Thread 'Understanding how to "tack on" the time wiggle factor'

Thread 'Understanding how to "tack on" the time wiggle factor'

The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
View full post »

Similar threads

Solving rotational motion without torque
Replies
12
Views
2K
Run-down of a wheel as a func. of time from full speed to standstill.
Replies
13
Views
2K
B The physics of flywheel launchers (like tennis ball shooters)
2
Replies
60
Views
4K
Landing Airplane Wheel Homework: Solving (a)-(e)
Replies
1
Views
2K
Rotating wheel with kinetic friction
Replies
1
Views
2K
Stopping a potter's wheel with a wet rag (angular momentum and friction)
Replies
1
Views
15K
B Questions about momentum and force as well as normal force/friction
Replies
35
Views
3K
Introductory rotational dynamics/energy conservation question
Replies
4
Views
2K
Coefficient of Kinetic Friction: Calculating from Homework
Replies
1
Views
1K
Why Is the Coefficient of Kinetic Friction Calculation Off by a Factor of 2?
Replies
3
Views
6K

Hot Threads

Recent Insights

Back
Top