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!

Moments using force and distance.

  1. Mar 29, 2010 #1
    1. The problem statement, all variables and given/known data

    The 4-kN force F is applied at point A. Compute the
    moment of F about point 0, expressing it both as a
    scalar and as a vector quantity. Determine the coordinates
    of the points on the x- and y-axes about which
    the moment of F is zero

    2. Relevant equations

    m=fd

    3. The attempt at a solution

    i think that i need to find the distance from F to the origin that is perpendicular. since the moment is always perpendicular to the line of action.
     

    Attached Files:

    • mom.jpg
      mom.jpg
      File size:
      5.9 KB
      Views:
      373
  2. jcsd
  3. Mar 29, 2010 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes, I think the easiest way is to break F into its x and y components, then solve for the moment about O by algebraically summing the moments produced by these component forces. Moments can be computed this way (force times perpendicular distance), but that is not the only way. Watch plus/minus signs!
     
  4. Mar 29, 2010 #3
    is there a simpler way to do this. i cant get my head round it. thanks
     
  5. Mar 29, 2010 #4

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You can use M=rFsintheta, where r is the magnitude of the position vector between O and A, F stars as itself, and theta is the included angle in between F and the position vector. I find it easier to break F into its x and y components, and then M_o = F_x(y) + F_y(x)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Moments using force and distance.
  1. Forces and Moments (Replies: 2)

  2. Moments Forces Help (Replies: 8)

Loading...