1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Torque: Table tipping

  1. Mar 1, 2015 #1
    1. The problem statement, all variables and given/known data
    http://imgur.com/dMw79w1 [Broken]

    The image contains the problem as well as the answers to the previous problems.

    2. Relevant equations
    Net torque = 0

    3. The attempt at a solution
    First, I set the axis of rotation to be the bottom of the table (where it goes through Fx and F0)
    τdue to downward forces = τdue to upward forces
    τvase + τtable + τcat = τdue to Fy (Fy (the solution to Fy is in the image)
    WvY + WtLy/2 + WmaxLy = Wt/2 + WvY/Ly

    Rearrange for Wmax:
    Wmax = Wt/2Ly + WvY/Ly2 - WvY/Ly - Wt/2

    The answer to the question is:
    Wmax = Wv(1 - X/Lx - Y/Ly)

    I don't know how to obtain this answer from my answer above.
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Mar 1, 2015 #2
    It seems that I forgot to include the distance the cat is from the axis of rotation (Ly). After including it, I got Wmax = 0.
  4. Mar 1, 2015 #3
    So here it the attempt once again:
    WvY + WtLy/2 + WmaxLy = (Wt/2 + WvY/Ly)(Ly)

    Rearranging for Wmax:
    WmaxLy = (Wt/2 + WvY/Ly)(Ly) - WvY - WtLy/2
    Wmax = Wt/2 + WvY/Ly - WvY/Ly - Wt/2
    Wmax = 0 N
  5. Mar 1, 2015 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The upward forces were calculated in the absence of a cat.
  6. Mar 1, 2015 #5
    The cat exerts a downward force on the table though (the weight), which is shonw by WmaxLy
  7. Mar 1, 2015 #6


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes, but you used the expressions obtained for Fx etc. in the first part. There was no cat then. The forces will be different now.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Threads - Torque Table tipping Date
Force by table leg Apr 29, 2015
Equilibrium and Torque of a table Dec 1, 2013
Torque: Overhanging Books on Table Mar 24, 2009
Table Torque Jan 2, 2005
Table Torque Issue Jan 1, 2005