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Gravity and the Rotation of Galaxies

  1. May 14, 2007 #1
    hey i need help! We are doing a lab on the above title and I have no idea how to do it.
    So there are few questions i wanted to know to ace this lab. lol i will really appreciate it if someone can help me.

    - Describe the differences between the two sets of data. Is the observed speeds explained by the equation
    v = √Gmg/ r ? Justify your answer

    -Briefly describe some of the methods astronomers use to estimate the mass of a galaxy, its radius and the value of G.

    Please, it will be really helpful if someone can help me!
  2. jcsd
  3. May 15, 2007 #2


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    Galaxy mass, usually by virial theory. Radius by observation. Both methods are approximate. G is assumed. Wiggle G and any result is possible.
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