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Homework Help: Kinetic Friction on inclined plane problem

  1. Oct 18, 2004 #1
    Been trying to comprehend this one for a few hours:

    The coefficient of kinetic friction between a block and an inclined plane is 0.20 and the angle is 60 degrees.

    What is magnitude of a? The book says 7.5 m / s^2
    How do I figure this with no speeds or distances or even a mass?
  2. jcsd
  3. Oct 18, 2004 #2
    you gotta do your free body diagrams!! those stupid things.... remember? the sum of all forces = ma unless the velocity is constant. do one for the x side and one for the y side, incorporate your co. of kinetic friction and the angle (probably cos60 and sin60 from mg)..... help any? i have a lot of trouble with these, too
  4. Oct 18, 2004 #3


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    Homework Helper

    Like doxi said use a freebody diagram then

    Apply Newton's 2nd Law

    [tex] \sum_{i=1}^{n} \vec{F}_{i} = m \vec{a} [/tex]
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