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!

Magnitude and Direction of Force

  1. Nov 2, 2008 #1
    1. The problem statement, all variables and given/known data

    http://img243.imageshack.us/my.php?image=61581222vi0.jpg
    http://xs433.xs.to/xs433/08440/untitled601.jpg

    I need to find the direction and the magnitude of F3 given only the figure and the resultant force of the 3 vectors =20 lb, plus F3 being the smallest force between all of them.

    3. The attempt at a solution

    Tried Rx and Ry and squaring them but I have 3 unknows in 1 solution...

    any ideas?
     
    Last edited: Nov 2, 2008
  2. jcsd
  3. Nov 2, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi chadovP! Welcome to PF! :smile:

    (have a theta: θ :wink:)

    I don't get it :confused:

    the only two unknowns are F3 and θ …

    what unknowns did you have? :smile:
     
  4. Nov 2, 2008 #3
    yes but there are sin θ and cos θ which makes the equation very complicated.
     
  5. Nov 2, 2008 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    ah!

    but that's still only one unknown!

    Hint: square, and add. :wink:
     
  6. Nov 2, 2008 #5
    2 unknows mate! F3 and the angle...
    so i have f3 sqaured and the angle in one equation and that the part i am not getting...
     
  7. Nov 2, 2008 #6

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    square, and add! :rolleyes:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?