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Rod on frictionless surface

  1. Oct 24, 2013 #1
    A rod initially held vertically is falling on a frictionless surface when given a slight push.I just want to how the rod would move.I am thinking that the rod as a whole will move forward and also rotate about the point on the ground.

    Why the rod is moving forward?(if you ask me)
    I think that the CM is going in circular motion and thus will experience an outward pull. This force will take the rod forward.

    But i have heard that the rod purely rotates and does not move forward as a whole.
    check this link http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2541
    What is wrong in my argument?
     
    Last edited: Oct 24, 2013
  2. jcsd
  3. Oct 24, 2013 #2
    I'm having trouble visualizing what you are saying. Could you be a little more explicit? Then I, as well as others, would be able to help you.
     
  4. Oct 24, 2013 #3
    here is a picture
    http://img191.imageshack.us/img191/3926/lyj9.png [Broken]

    I want to know if the rod will rotate purely or have a translational velocity with rotation?
     
    Last edited by a moderator: May 6, 2017
  5. Oct 24, 2013 #4
    If the surface is frictionless ,as in the picture,the lower end slips on the surface towards right ,in a manner such that the CM of the rod moves vertically downwards .You can consider the motion of the rod as a combination of translation of CM + Rotation around the CM.

    I have made a rough sketch .The red dot shows the CM.
     

    Attached Files:

  6. Oct 24, 2013 #5
    For the end to slip should there be any net force acting on it?
     
  7. Oct 24, 2013 #6
    I got it
    thanks a lot:smile:
     
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