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Kinetic rotational energy problem

  1. Jan 30, 2012 #1
    1. The problem statement, all variables and given/known data

    A diatomic molecule can be modeled as two point masses, m1 and m2, slightly separated. If the molecule is oriented along the y-axis, it has kinetic energy K when it spins about the x-axis. What will its kinetic energy (in terms of K) be if it spins at the same angular speed about

    (a) the z-axis
    (b) the y-axis?

    2. Relevant equations

    K = 0.5Iω2

    3. The attempt at a solution

    (a) I stays the same as the atoms are the same perpendicular distance from the origin. So the kinetic energy = K.

    (b) I = 0 as the perpendicular distance between each atom and the rotation axis (the y-axis) is 0. So, kinetic energy = 0.

    It would help me if you comment on my solution.
  2. jcsd
  3. Jan 31, 2012 #2

    Simon Bridge

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    Looks good to me.
    Was there anything in particular you were concerned about?
  4. Feb 1, 2012 #3
    Oh no, just wanted to know if my answers were good. Thanks, by the way!
  5. Feb 1, 2012 #4

    Simon Bridge

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    No worries.
    Looks like you need to develop ways to decide for yourself if your answers are good.
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