1. Not finding help here? Sign up for a free 30min 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!

Moment of inertia question

  1. Mar 20, 2007 #1
    1. The problem statement, all variables and given/known data

    When a ceiling fan rotating with an angular speed of 2.40 rad/s is turned off, a frictional torque of 0.227 Nm slows it to a stop in 6.65 s. What is the moment of inertia of the fan?

    2. Relevant equations

    3. The attempt at a solution

    In almost all of the moment of inertia equations, they involve a radius. there is no radius given in the problem. i tried to use K= 1/2 I w^2. Im really stuck and dont know what to do next.
  2. jcsd
  3. Mar 20, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    You don't have the data to compute the moment of inertia directly. Instead, deduce the moment of inertia by applying Newton's 2nd law for rotation. Hint: First compute the angular acceleration using kinematics.
  4. Mar 20, 2007 #3
    Thanks so much! i just got it right on the webassign
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Moment of inertia question