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Find the coefficient of static friction help?

  1. Sep 30, 2008 #1
    1. The problem statement, all variables and given/known data
    An object rests on an inclined plane. One end of the plane is lifted until the object begins to slide. If the angle at which the object begins to slide is 35 degrees, what is the coefficient of static friction?

    2. Relevant equations
    Possibly Fk=("mew"k)N

    3. The attempt at a solution
    Not even sure where to begin, just knowing the angle can I even solve this problem. Thanks for the help I really appreciate it.

  2. jcsd
  3. Sep 30, 2008 #2
    You need the mass of the object at the least to solve the problem. Otherwise, this is an impossible problem.
  4. Oct 1, 2008 #3
    I talked to a TA at my college, he wouldn't really help me but he said its not that bad of a problem, and to just plug in M for mass, and hope it cancels out when you solve the equations. I'm still a bit confused, so anyones input is greatly appreciated. Thanks a lot.
  5. Oct 1, 2008 #4


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    Yes, the TA is correct. The object is just on the verge of sliding , but still at rest, when the angle reaches 35 degrees. Therefore, Newton 1 applies, where the max friction force up the plane, F_s =(mu)_s(N) (not F_k or mu_k, which you have incorrectly noted) is balanced by the object's weight component down the plane. Hope that the M cancels when you solve the equation.
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