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: Help with Torque Problems

  1. Sep 20, 2011 #1
    1. The problem statement, all variables and given/known data

    I need help with #2 and #5.

    #2 just aks what is the mass of m1, in order for the system to be in static equilibrium

    #5 aks what angle will the disk spin when pushed to go up that step. It also asks what is the minimum force needed in order for the disk to go up.

    3. The attempt at a solution
    I tried solving #2 just like i did with #1. They are giving me 2 sets of distances (in #1 just one) i also tried with the other set of distances and it didnt work. I even tried combinating the 2 sets of distances and not even that works.

    For #5 tried combinating some formulas:

    _______________ = a/r = ΔΘ/Δt

    but all of those unkowns ''freak me out''

    EDIT: and you can see that my teacher has an answer bank, i know that Θ is obviously 30, but i dont know how to get there

    Attached Files:

  2. jcsd
  3. Sep 20, 2011 #2


    User Avatar

    Staff: Mentor

    For #2, can you identify all the masses that are exerting torques about the pivot point? What are they, and where are their centers of mass located?
  4. Sep 25, 2011 #3
    i keep getting 130kg, which is not on the answer bank, im i doing it wrong or did the teacher made a mistake with the answer bank?????
  5. Sep 25, 2011 #4


    User Avatar

    Staff: Mentor

    You'll have to show your work before we can comment on why or where you might be making a mistake. What choices does the answer bank give?
  6. Sep 26, 2011 #5
    no don't worry about it, i finally got the right answer, i just saw things from another perspective (because i dont know about you, but i tend to commit the same error more than once) and got it
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook