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Homework Help: Motions with frictions

  1. Oct 11, 2008 #1
    1. The problem statement, all variables and given/known data

    http://img406.imageshack.us/img406/6092/testdd5.th.jpg [Broken]http://g.imageshack.us/thpix.php [Broken]

    find the fk in terms of M,m,a

    2. Relevant equations

    3. The attempt at a solution

    So what I got in the end result after decomposing the forces on each object and then do a substitution is :

    fk = m(a+g) - Ma,

    where m is the mass of the hanging block and M is the mass of the object in the plane. Is this wrong?
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 11, 2008 #2


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    Staff Emeritus
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    Homework Helper

    I think your expression for T is incorrect. It may have to do with defining + and - directions.

    In your +/- convention: if "a" is positive, do the blocks accelerate to the left & up, or to the right & down?
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