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!

Homework Help: Determine the distance of the center of gravity from the end X of the plank?

  1. May 18, 2008 #1
    1. The problem statement, all variables and given/known data
    A non-uniform plank of wood XY is 2.50m long and weighs 950N. Force-meters (spring balances) A and B are attached to the plank at a distance of 0.40m from each end, as illustrated in the Figure below

    http://img266.imageshack.us/img266/2377/physicsp23bgh5.png [Broken]​
    [/URL]
    When the plank is horizontal, force-meter A records 570N

    (i) Calculate the reading on force-meter B
    (ii) Determine the distance of the center of gravity from the end X of the plank.

    2. Relevant equations
    Moment = Force x Perpendicular Distance

    3. The attempt at a solution
    (i) [tex]A + B = 950N[/tex]
    [tex]B = 950 - 570 = 380N[/tex]

    (ii) I don't know how to solve this question, need help! :frown:
     
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. May 18, 2008 #2

    CompuChip

    User Avatar
    Science Advisor
    Homework Helper

    In equilibrium, all the moments (A, B, gravity) cancel out.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook