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!

Centroid of a C-Shape

  1. Sep 11, 2012 #1
    1. The problem statement, all variables and given/known data

    http://prntscr.com/fcbm8

    Find the centroid - All dimensions are in mm

    2. Relevant equations

    xbar = (A1X1+A2X2) / (A1+A2)

    Similarly for Ybar I assume

    3. The attempt at a solution

    I got the y co-ordinate to be 20.428mm, and would assume that the x coordinate would be 5mm.

    Is this right?
     
  2. jcsd
  3. Sep 11, 2012 #2

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    You can divide the shape into three rectangular parts several different ways but I used two vertical lines in the obvious places. I assumed the origin is in the bottom left corner.

    xbar = (A1X1+A2X2+A3X3) / (A1+A2+A3)

    = (700*5 + 800*30 +400*30) / (700+800+400)
    = 20.789

    ybar = (A1Y1+A2Y2+A3Y3) / (A1+A2+A3)

    = (700*35 + 800*10 + 400*65) / (700+800+400)
    = 30.789

    Best show your working as my answer is quite different.
     
  4. Sep 11, 2012 #3
    This is what confused me, does this mean the centroid is not on the shape itself?
     
  5. Sep 11, 2012 #4

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    In this case yes. Where would the centroid of a doughnut be?
     
  6. Sep 11, 2012 #5

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    In the center, of course. That's what the "centroid" is- the geometric center. If you were to represent the doughnut as two circled in the in the xy-plane, centered at the origin with radii r and R, and then have other circles as the thickness of the doughnut, the centroid would be at (0, 0, 0).
     
  7. Sep 12, 2012 #6

    CWatters

    User Avatar
    Science Advisor
    Homework Helper

    I know. I was using it as an obvious example for the OP to think about. eg a shape that has a centroid that's not on the surface of the shape.
     
  8. Sep 12, 2012 #7
    Yeah, I was probably thinking more about a centroid of a mass, but even then, there's still the donut which proves me redundant.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Centroid of a C-Shape
  1. Centroid of shape (Replies: 4)

  2. Centroid question (Replies: 3)

  3. Finding Centroids (Replies: 20)

Loading...