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Homework Help: Rotating surface/friction question

  1. Mar 24, 2009 #1
    1. The problem statement, all variables and given/known data
    http://img10.imageshack.us/img10/9781/probs.jpg [Broken]

    3. The attempt at a solution
    Hey guys, I understand how to find the static friction point (equate mv2/r to max static friction). However, I'm confused as to which direction (in to out or out to in) is the correct one ie. from kinetic slipping to 'sticking'. At the moment I'm thinking it's outside in (Jo's answer) but I can't justify it properly. Thanks!!
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Mar 24, 2009 #2


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    Homework Helper

    You've determined the boundary where it starts to slip. And the boundary is dependent on

    μ*m*g > m*ω²*r


    r < μ*g/ω²

    This means that outside this distance it slips doesn't it? If the aim is to have it slip until it grabs then ...
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