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Homework Help: Help on Uniform Circular Motion Problem Please!

  1. Oct 1, 2007 #1
    1. The problem statement, all variables and given/known data

    1. The problem statement, all variables and given/known data

    Derive a formula for the bullet speed v in terms of D, T, and a measured angle between the position of the hole in the first disk and that of the hole in the second. If required, use [tex]\pi[/tex], not its numeric equivalent. Both of the holes lie at the same radial distance from the shaft. [tex]\theta[/tex] measures the angular displacement between the two holes; for instance, [tex]\theta[/tex]=0 means that the holes are in a line and means that when one hole is up, the other is down. Assume that the bullet must travel through the set of disks within a single revolution.

    A diagram of this can be found here: http://ca.geocities.com/canbball/MRB_rr_8_a.jpg [Broken]

    2. Relevant equations

    Okay so I know that v=D/t
    And that v = (2[tex]\pi[/tex]r)/T

    3. The attempt at a solution

    I know that the disks rotate by 2 in time T. What I don't understand is how to express this in terms of [tex]\theta[/tex].

    Any help would be greatly appreciated!
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 2, 2007 #2
    Can you state the angular velocity, omega, in terms of the angle theta?

    In step 3, you've dropped a pi.
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