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G within a thin disk

  1. Aug 4, 2013 #1
    I'm researching dark matter and how it affects galaxy rotation curves, I came up with the problem below.

    Imagine a very thin, flat disk which has uniform mass per unit area.

    What is the gravitational field strength (g) within the disk itself? How does g vary with respect to r, the distance from the center of the disk.

    The area density of the disk is δ and the radius of the disk is R.
  2. jcsd
  3. Aug 5, 2013 #2


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  4. Aug 5, 2013 #3

    Most of the threads focus on the z-axis. But in order for me to simulate a galaxy, I have to focus on the x-axis.

    I came up with an integral to find the value of g, but its value ends up being infinite.

    I can write it down step-by-step to let you guys find out where I went wrong.
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