1. Not finding help here? Sign up for a free 30min 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!

Finding the coefficient of static friction

  1. Mar 11, 2010 #1
    1. The problem statement, all variables and given/known data
    If a curve with a radius of 85m is properly banked for a car traveling 65 km/h what must the coefficiant of static friction be for a car not to skid when traveling at 95km/h


    2. Relevant equations
    For this question i tried using a few equations such as centripical force, force friction where Ffric = UsFn aswell as (mv^2)/R = Ffric i also though the equation Tan(theta)=V^2D/Rg was pertanent.


    3. The attempt at a solution
    I set up a proportion of mv^2/R = Us(ma) and the masses canceled out so i was left with v^2/ra but i didnt really know where to go from here.
     
  2. jcsd
  3. Mar 11, 2010 #2
    Welcome to Physics Forum, although I am quite new too.
    The car is moving on a banked curve. Did you take in account the part of the normal force that points towards the centre [tex]N_{x}[/tex]? Also, you should also break the friction force into components [tex]f_{x}[/tex] and [tex]f_{y}[/tex].
     
  4. Mar 11, 2010 #3
    Ok i set up my two force components and i have Fycos(theta)=mg and Fxsin(theta)=mv^2/r when dividing both components together you are left with tan(theta)=v^2/rg and when i plug in the numbers given after converting 95 km/h to m/s you get a static friction of .81 am i doing somthing wrong because it doesn't seem right
     
  5. Mar 11, 2010 #4
    What did you mean by Fy and Fx?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Finding the coefficient of static friction
Loading...