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Homework Help: Seemingly Simple - How Many Orbits? (Rotational Kinematics)

  1. Oct 22, 2006 #1
    This is the latest question I've been stuck on.

    The Bohr model of the hydrogen atom pictures the electron as a tiny particle moving in a circular orbit about a stationary proton. In the n=2 orbit, the distance from the proton to the electron is 21.16e-11 m , and the linear speed of the electron is 1.09e6 m/s.

    How many orbits about the proton does it make each second?

    Now, I found the angular velocity of the electron and got that correct: 5.15e15 rad/s. Now, to find the # of orbits, shouldn't I just convert to revolutions per second, which is 8.09e15 rev/s? The computer tells me I'm wrong, however, but I don't know what I could do differently.

    Again, I appreciate your time!
  2. jcsd
  3. Oct 22, 2006 #2


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    I promise you that it is impossible to do more full revolutions than radians in the same amount of time. Your angular velocity looks good; your conversion does not.
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