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!

Static Equilibrium and Torque

  1. Nov 17, 2013 #1
    wrong section
     
    Last edited: Nov 17, 2013
  2. jcsd
  3. Nov 17, 2013 #2
    1. The problem statement, all variables and given/known data
    I have been trying to solve this problem for a while now and I can't figure out what I am doing wrong...

    Here is the problem:

    In the figure below, a horizontal scaffold, of length 2.00 m and uniform mass 50.0 kg, is suspended from a building by two cables. The scaffold has dozens of paint cans stacked on it at various points. The total mass of the paint cans is 75.5 kg. The tension in the cable at the right is 780 N. How far horizontally from that cable is the center of mass of the system of paint cans?

    12-32.gif


    2. Relevant equations

    T = r x F

    Sigma T = 0

    3. The attempt at a solution

    What I am doing is using the left cable as the rotational axis for Torque. So I get Torque due to the beam + torque due to the CoM of the paint cans = 780N

    Therefore, (50)(9.8)(1m) + (75.5)(9.8)(x) = 780N

    The answer is supposed to be .554 m. So I think I'm missing a force but I don't know what it is. Thanks for your help :)
     
  4. Nov 17, 2013 #3

    adjacent

    User Avatar
    Gold Member


    Welcome to PF,Itachi (don't use sharingan on me) lol :wink:
    The scaffold is in equillibrium.So,clockwise moment is equal to anticlockwise moment.You're 780N is wrong,it has to be the torque there.
    780 x 2=1560Nm.
    You are using the other cable as a reference point.So,you will get the distance from.Therefore,you have to subtract it from 2m. o:)
     
  5. Nov 17, 2013 #4

    adjacent

    User Avatar
    Gold Member

    Welcome to PF,Itachi (don't use sharingan on me) lol :wink:
    The scaffold is in equillibrium.So,clockwise moment is equal to anticlockwise moment.Your 780N is wrong,it has to be the torque there.
    780 x 2=1560Nm.
    You are using the other cable as a reference point.So,you will get the distance from.Therefore,you have to subtract it from 2m.o:)
     
  6. Nov 17, 2013 #5
    Thank you!!
     
  7. Nov 17, 2013 #6

    adjacent

    User Avatar
    Gold Member

    You are welcome
     
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: Static Equilibrium and Torque
Loading...