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Homework Help: Mass inside galaxy

  1. Mar 18, 2005 #1
    I have another exam question, which I'm having some slight problems with...

    "In a particular galaxy the velocity curve is constant over a large range of radii, and equal 300 km/sec at a particular radius of 10kpc in this range. Estimate the mass inside this radius."

    Can I use centrifugal force equals gravitational force to derive M? This is what I'm trying to do. What I'm getting confused about, is if the constant velocity inside 10 kpc have any affect on M.

    Very grateful for any help or suggestions!

  2. jcsd
  3. Mar 18, 2005 #2
    well, the fact that the velocity is constant does say something about the mass of the galaxy as a whole, but in your case, since you're only dealing with mass in this radius, than you can use mechanics to solve your question.


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