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Homework Help: Friction (horizontal) Applied Greater Force than Equilibrium

  1. Sep 26, 2010 #1
    1. The problem statement, all variables and given/known data
    When you apply a horizontal force of 44 N o a block, the block moves across the floor at a constant speed (μk = μs). When you apply a force of 50 N, what is the magnitude of the horizontal component of the force that the floor exerts on the block?

    2. Relevant equations
    ffriction ≈ μkFN

    3. The attempt at a solution

    I'm not sure how to go about this. If the question asks for the horizontal force, do I still need to use the force of gravity in my calculations?

    An explanation is appreciated, with or without the answer. I want to know how to do this, not necessarily know what the answer is.
  2. jcsd
  3. Sep 26, 2010 #2


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    The floor exerts both a perpendicular (Normal) force in the vertical y direction, and a friction force in the horizontal direction, opposite the relative motion between the block and floor. The book is looking for the horizontal force component of the floor on the block.
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