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Homework Help: Bracket/block static friction problem (physics)

  1. Sep 23, 2009 #1
    1. The problem statement, all variables and given/known data
    http://img3.imageshack.us/img3/6618/5n6.jpg [Broken]
    Image there.

    2. Relevant equations
    Well this is actually where the problem occurs. You make your own equations.

    3. The attempt at a solution
    It's the friction that is really messing me up. I'm just so confused, I'm going to show you my attempt at FBDs for the problem.

    I think that if I just know how to draw them correctly I'll be able to find my answer, unless there is some other tricky way to get it.

    Okay so for the 12kg block, we have:

    m1g going DOWN
    n1 going UP
    T to the LEFT
    fs to the LEFT

    And for the 7kg bracket, we have:

    m2g going DOWN
    n2 going UP
    n1 going DOWN
    T to the RIGHT?
    fs to the RIGHT

    Apparently I didn't draw them correctly because when I try to solve for something, there are always two variables... other than f = Mu*N which equals 94.08 N.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Sep 23, 2009 #2
    Did I mention this is due soon? Please everyone, I really need your help.
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