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: Pulleys and forces

  1. Apr 5, 2008 #1
    1. The problem statement, all variables and given/known data
    An object of mass 12.5 kg hangs from very light pulleys as shown here:
    What force must be applied to the rope so that the mass stays at rest?

    2. Relevant equations
    Fnet = ma.....

    3. The attempt at a solution
    I am really clueless when it comes to this question. I know the net force must be 0 because there is no acceleration occuring b/c it must be at rest. Please help.
  2. jcsd
  3. Apr 5, 2008 #2
    You are correct by saying that the net force must be 0, since the system will be in static equilibrium.
    Try drawing a free body diagram for each pulley.
    If you correctly label the tensions in the strings and sum up the forces in both the x and y directions, the problem will become much easier.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook