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!

Statics- equilibrium of rigid bodies

  1. Nov 15, 2013 #1
    1. The problem statement, all variables and given/known data

    An opening in a floor is covered by a 1×1.2-m sheet of plywood of mass 18 kg. The sheet is hinged at A and B and is maintained in a position slightly above the floor by a small block C. Determine the vertical component of the reaction (a) at A, (b) at B, (c) at C.

    2. Relevant equations

    3. The attempt at a solution

    I know how to approach this problem, however, im just a bit confused on how to set up my F.B.D. i attached the correct f.b.d for this problem . My question is, how come if we take the moment about point A, we only have a reaction force in the j direction at support B?

    Attached Files:

  2. jcsd
  3. Nov 15, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    The plywood is hinged at A and B and the only loads imposed are the weight and the reaction due to the block at C. All of these forces are in the direction of the y-axis. It doesn't matter about which point you take moments, it's just the nature of the forces for this particular problem.
  4. Nov 15, 2013 #3
    You take moments about an axis, not a point. That is the key to solving 3-dimensional problems like this.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Statics- equilibrium of rigid bodies