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!

Moments of Inertia of a rod

  1. Nov 14, 2006 #1
    The moment of inertia about an axis along the length of a rod is zero, correct?
     
  2. jcsd
  3. Nov 14, 2006 #2

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    Almost. If the rod has a measurable radius, it is a cylinder.
     
  4. Nov 15, 2006 #3
    In all the other parts ot the problem though I considered it a rod.

    Here's the problem:

    Find the moment of inertia about each of the following axes for a rod that is 0.280 cm in diameter and 1.70 m long, with a mass of 5.00×10−2 kg.

    A. About an axis perpendicular to the rod and passing through its center.
    I = (1/12)ML^2
    I = .012 kgm^2

    B. About an axis perpendicular to the rod passing through one end.
    I = (1/3)ML^2
    I = .048 kgm^2

    C. About an axis along the length of the rod.
     
  5. Nov 15, 2006 #4

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    The rod has a diameter. It has a moment of inertia about the long axis.
     
  6. Nov 15, 2006 #5
    So, I = (1/4)MR^2 + (1/3)ML^2 ?
     
  7. Nov 15, 2006 #6

    Doc Al

    User Avatar

    Staff: Mentor

    The length of the stick--or cylinder--parallel to the axis doesn't matter, only the radius.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Moments of Inertia of a rod
  1. Moment of inertia (Replies: 3)

  2. Moment of Inertia (Replies: 1)

Loading...