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Homework Help: Another Friction Equilibrium Problem

  1. Nov 25, 2008 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations
    Sum of forces in X, Y, f/n= coefficient of friction

    3. The attempt at a solution

    I tried looking at this as a 3 force member, since the lines of action of the normals and the weight intersect at a point, but I am not sure where to go from there. Or where the 4m length comes into play.
  2. jcsd
  3. Nov 25, 2008 #2


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    Homework Helper

    I think what you need to do is draw in the tangents at the points of contact and that should give you the basic equation that balances the piece and keeps it in equilibrium.

    Where the diameter and length comes in I think is in determining what the component angles are at the contact points.

    I think using the relationship that a chord length of a circular section is given by

    C = 2*R*Sin(θ/2)

    You can calculate the angle that the bar subtends at the center of the circle and then you should be able to calculate those angles.

    (See: http://mathworld.wolfram.com/CircularSegment.html )
  4. Nov 25, 2008 #3
    Hmm, ive never seen that forumla before. Does it work when the "c" is slanted anywhere? So did, I use that eqaution correctly? I got theta = 101.61 degrees
    Last edited: Nov 25, 2008
  5. Nov 25, 2008 #4


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    I got it from the link I supplied.

    Looks like 101.6 degrees to me as well.
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