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Homework Help: Accelerating Wedges with Friction

  1. Jul 16, 2010 #1
    1. The problem statement, all variables and given/known data

    A block rests on a wedge inclined at an angle [tex]\theta[/tex]. The coefficient of friction between the block and the plane is [tex]\mu[/tex].


    Let the wedge move with horizontal acceleration a to the right. Assuming
    that tan [tex]tan(\theta) < \mu[/tex], find the minimum value of a for the block to remain on the wedge without sliding.

    Also find the maximum value of a.


    2. Relevant equations

    3. The attempt at a solution

    [tex]mgcos(\theta)+masin(\theta)=F_{normal};
    \tex{mgcos(\theta)+\mu (F_{normal})=macos(\theta);

    a=\frac{g(sin+\mu cos}{cos - \mu sin}[/tex]

    which gives wacky limiting values and isn't a range at all but just one value.
     
    Last edited: Jul 17, 2010
  2. jcsd
  3. Jul 17, 2010 #2
    Have a bit correction with this one: [tex]F_{static friction} \leq \mu F_{normal}[/tex]
    Also, there must be a condition for a to be positive, as a acts to the right.
     
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