×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Friction Torque on a Rotating Disc

Friction Torque on a Rotating Disc

Friction Torque on a Rotating Disc

(OP)
thread404-264188: Friction Torque on Rotating Disk

On the thread listed above I was looking at it and had a question on how the final formula (T=mu*F*R*2/3) was formulated.

when i take the double integral of r*dr*dthetha with the bounds of 0 to R and 0 to pi I get pi*R^2/2.

I take P = F/A and A = pi*R^2/4

so substituting I get T=2*mu*F*R

Can someone help me on this.

Thanks,
Matt

RE: Friction Torque on a Rotating Disc

Part of the derivation is given as rdA where dA = rdr, so the equation is r^2dr -> r^3/3.

RE: Friction Torque on a Rotating Disc

(OP)
sorry A = pi*r^2, so still using r^3/3 and substituting back in would still only give you 1/3*F*R*mu.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources