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: Moment of Inertia of a pulley

  1. Apr 1, 2010 #1
    1. The problem statement, all variables and given/known data
    A 1.65 kg mass is attached to a light cord that is wrapped around a pulley of radius 4.65 cm, which turns with negligible friction. The mass falls at a constant acceleration of 2.40 m/s2. Find the moment of inertia of the pulley.

    2. Relevant equations
    I=mr^2
    Torque=I*alpha


    3. The attempt at a solution
    I tried to just square the radius given and multiply it by the mass but that did not work. I also tried to find the Torque using T=mgr. And then divided that number by the acceleration/radius in order to get the angular acceleration.
     
  2. jcsd
  3. Apr 1, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    So what did that give you?
     
  4. Apr 1, 2010 #3
    It gave me the wrong answer. I guess that is not the correct way to find the torque
     
  5. Apr 1, 2010 #4

    rock.freak667

    User Avatar
    Homework Helper

    That should be the correct way to do it, post your work.
     
  6. Apr 1, 2010 #5
    I figured it out using a different set of equations. Thanks for your help though, sorry to waste your time.
     
  7. Apr 1, 2010 #6

    rock.freak667

    User Avatar
    Homework Helper

    What equations did you use by chance?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook