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Homework Help: Force of Friction Equation?

  1. Jan 26, 2004 #1
    I think the reason that my problems have arisen is because of my equation for the force of friction. I have

    Ff= ucosAngle

    That right?
  2. jcsd
  3. Jan 26, 2004 #2


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    The force due to friction:

    [tex]F = \mu N = \mu m g[/tex]

    Where [itex]\mu[/itex] is the coefficient of friction (either static of kinetic), and [itex]N[/itex] is the normal force. On a horizontal plane, the normal force is just the weight of the object, which is [itex]mg[/itex].

    - Warren
  4. Jan 29, 2004 #3
    And to include the angle;
    F_f=\mu mg cos \alpha
  5. Jan 29, 2004 #4
    It is the limiting force of friction or say max friction force exerted and f force due to friction depends on the circumstance

    For eg moving on a plane surface Chroots Ans is correct and in case if body is on inclined surface Kishtiks Ans is correct
  6. Jan 30, 2004 #5
    I love my equation. What is the angle for a plane surface? 0? Then what is cos0? 1? Then what is 1.mu mg? mu mg? Are the two eqs the same?:smile:
  7. Jan 30, 2004 #6
    lol rofl same eq man.
  8. Jan 30, 2004 #7
    It is not same equation

    It is the case of the equation under the given conditions only
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