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!

Weighed Centroid Proof?

  1. Aug 13, 2012 #1
    Given the formula for the weighted centroid, C of a system of parallel forces
    Fi acting at points Pi, show that two weights W and 3W, acting respectively
    at points P1, P2, are together equivalent to a single weight 4W acting at P,
    where P lies on the line segment joining P1 to P2 and P1 P : P P2 = 3 : 1.

    OC = (Ʃi opi.Fi)/ (ƩFi)

    Any one know how to prove it ? revising and this came up in a test last year its not in my notes?
  2. jcsd
  3. Aug 15, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Is that the formula as you're given it? The forces are vectors, so it would more logically be written
    OC. (ƩFi) = (Ʃi opi.Fi)
    You have the choice of where to place the origin. Where will you place it? Having done that, can you fill in the RHS of the formula using the W & 3W set-up?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook