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Homework Help: Force of friction on a block

  1. Nov 2, 2008 #1
    1. The problem statement, all variables and given/known data
    As shown in the figure, a block is pushed up against the wall. Let the mass of the block be m=2.3 kg, the coefficient of kinetic friction between the block and the wall be µ= 0.53, and θ= 62. Suppose F = 68 N.
    The acceleration of gravity is 9.8 m/s^2.
    Find the force of friction. Answer in units of N.

    2. Relevant equations
    Fk= µ ( F sin θ - mg)

    3. The attempt at a solution
    Well first I used F= µ(F sin θ), but I figured it was too simple, so I drew a free body diagram and saw mg going down on the block. I'm not sure how to go from there. Does the vertical component of force equal mg?
  2. jcsd
  3. Nov 2, 2008 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Yes, the sum of the vertical components must be equal to the weight of the block.
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