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: Torque and force

  1. Nov 19, 2005 #1
    hey. I got a bunch of questions based on this idea, so i wanna make sure i got it right before i do everthing.
    lets say i got a board sitting between 2 supports A & B. with a length L and a centre of mass x from A. i need to find the force of both endpoints on the supports.
    would it be forceA = mg(L-x)L and forceB = mg(x)L ?

    thanks
     
  2. jcsd
  3. Nov 19, 2005 #2
    Almost. Taking moments about the two supports and you get.

    forceA=mg(L-x)/L and forceB=mg(x)/L

    A quick way to check this is that for static equilibrium the downwards forces must equal the upwards forces. In this case, forceA + forceB = mg
     
  4. Nov 19, 2005 #3
    oh geez. that IS actually what i had done. Honestly. Why won't u believe me?!!!!!
    I just switched it in my head going from paper to computer.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook