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Homework Help: Coefficient of friction formulas help

  1. Nov 3, 2004 #1
    A 52-N sled is pulled across a cement sidewalk at a constant speed. A horizontal force of 36 N is exerted. What is the coefficient of sliding friction between the sidewalk and the metal runners of the sled?
    What formulas would I use in this problem?
     
  2. jcsd
  3. Nov 4, 2004 #2

    It is simple !
    Use the formula,
    [TEX] F = {\mu}_s * N [/TEX]
    where F is the horizontal force and N is the normal force, which is equal to the weight of the sled. (I assume that the cement sidewalk is placed horizontally).
     
    Last edited: Nov 4, 2004
  4. Nov 6, 2004 #3
    Notice that the body is moving with uniform accelaration.
    This means that the net force acting on the body is 0.
    Therefore, [tex]\mu * 52 N = 36 N[/tex]
    This gives, [tex]\mu = 36 / 52[/tex]
     
  5. Nov 6, 2004 #4

    brewnog

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    Science Advisor
    Gold Member

    The body is moving with uniform *velocity*, not acceleration, otherwise the net force on the body would not be zero.
     
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