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Circular Motion of two objects

  1. Oct 7, 2003 #1
    i have a question which i have been told about but i still dont udnerstand...
    ok..
    you have two objects(say they are made out of wood):

    1: *-------------* ...... 2: *---------
    ..............|....................................|
    ..............|....................................|
    ..............|....................................|
    ..............|....................................|
    ..............|....................................|
    ..............|....................................|

    "*" represents 1kg wieghts
    "..." represent nothin, i needed to put those there so the picture would position correctly. Just say it is open air :)

    you supply a torque to object number 1, you will notice that is spins perfectly. While if you supply a torge to number 2 it will wobble and isnt perfect like number 1.

    so what i want to know is.. why does number 2 wobble?

    its hard to explain the question, but i hope you all understand

    also the torque is supplied at the rod:
    ........|
    ........|
    ........|
    ........|
    ........|
     
    Last edited by a moderator: Oct 7, 2003
  2. jcsd
  3. Oct 8, 2003 #2
    Number two wobbles because there is an unbalanced centripetal acceleration. Given a point mass at radius r, and instantaneous velocity v, centripetal acceleration c is given by:
    c=(v^2)/r
    or if you use angular velocity (w is omega):
    c=(w^2)r
    In case you usually use rpm, I think v=rpm*Πr/30 and w=rpm*Π/30.
     
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