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: Deriving an equation through a free body diagram

  1. Nov 3, 2011 #1
    1. The problem statement, all variables and given/known data
    Use a Free body diagram to show that :Tanθ=static friction, on an incline plane

    2. Relevant equations

    FF/FN= coeficiant of friction

    3. The attempt at a solution
    I know I must get an angle to have a tan of the Force of friction and a Normal force, but I don't understant why i need the the angle
  2. jcsd
  3. Nov 4, 2011 #2


    User Avatar
    Homework Helper

    You should draw out the free body diagram (since that's what the question asks) and that's usually the best way to go about solving these kinds of questions anyway.

    What was the actual question? It would make more sense if it asked you to show that:
    [tex]tan(\theta) \leq \mu_s [/tex]
    (where [itex]\mu_s[/itex] is the coefficient of static friction). And remember that the friction force can be less than its maximum possible value, which is why there is an inequality sign.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook