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!

Pivoting rod about the center

  1. May 24, 2005 #1

    A uniform rod is pivoted at its center and a small weight of mass M = 5.15 kg is rigidly attached to one end. The rod has length L = 4 m and mass mrod = 12.4 kg. The system is released from rest at the q = 37° angle. The angular acceleration just after it is released is 2.17rad/s^2. What is the angular velocity when the rod is vertical?

    To do this, you can use the energy conservation. Change in potential energy of the rod plus the change in potential energy of the weight equals the kinetic energy. KE = (1/2)IW^2 = delta total Potentional energy. You get the change in potential energy by finding the delta PE of weight and the rod. delta PE of weight is simply M*G*(change in Height), but how do you find the change in PE of the rod???
  2. jcsd
  3. May 24, 2005 #2


    User Avatar
    Science Advisor
    Homework Helper

    The potential energy of the rod does not change because the pivot point is the center of mass.
  4. May 24, 2005 #3
    thats what i thought too. i wasnt getting the right answer, but i guess i did the calculations wrong. thanks !
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Pivoting rod about the center
  1. Rod about fixed pivot (Replies: 9)