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Homework Help: Work done by friction on an incline plane

  1. Mar 16, 2013 #1
    1. The problem statement, all variables and given/known data


    Could someone check my work to make sure I'm doing this problem correctly?
    s : hypotenuse or distance
    h : height
    uk : coef friction

    2. Relevant equations

    W = F*D
    Force Normal = mgcosθ
    Wfriction = (uk * N) * s(distance)

    3. The attempt at a solution
    Solve for θ to use to find force normal
    Sinθ = h / s
    θ = arcsin(h/s)

    Y component of weight of box = mgcos*arcsin(h/s)
    Fy = may = N - mgcos*arcsin(h/s)
    N = mgcos*arcsin(h/s)

    Then plug N into equation Wfriction = -uk * N * s
    Wfriction = -uk*mgcos*arcsin(h/s)*s
  2. jcsd
  3. Mar 16, 2013 #2

    rude man

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    After a few extraneous equations, the result looks right.
  4. Mar 16, 2013 #3
    Thank you Rude man, but how would I remove the extraneous equations? Could you show me an alternate shorter way to go about doing this?

    Also, would I have to solve for a when using Fy = may = N - mgcos*arcsin(h/s)?
    Last edited: Mar 16, 2013
  5. Mar 16, 2013 #4

    rude man

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    see above.
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