1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook