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: Introductory Torque Statics Problem

  1. Feb 9, 2015 #1
    1. The problem statement, all variables and given/known data
    You're carrying a 4.0-m-long, 24kg pole to a construction site when you decide to stop for a rest. You place one end of the pole on a fence post and hold the other end of the pole 35 cm from its tip.

    I've drawn a diagram of the problem on Paint...

    2. Relevant equations

    3. The attempt at a solution
    I know that ∑τ=F(r1)+w(r2)+N(r3)=0, and I'm going to rewrite it so F(r1)+N(r3)=-w(r2). Now, if I call the left-most point the pivot point, my new equation becomes F(.35m)+4m(9.8 N/kg * 24kg) =-2m(-9.8 N/kg* 24 kg), which simplifies to F(.35m) = -470.4Nm, which makes F=-1344N. This seems way too big to be right; what did I do wrong?
  2. jcsd
  3. Feb 9, 2015 #2


    User Avatar
    Homework Helper

    it would be much easier to use the RIGHTmost point as the pivot. Where is the weight applied? ... why are you not adding torques to zero? ...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted