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Homework Help: Two problems involving angular velocity:

  1. Oct 4, 2007 #1
    Two problems involving angular velocity:

    Edit: Problem one solved! Hooray!

    2.The Milky Way galaxy rotates about its center with a period of about 192 million years. The Sun is 2x10^20 m from the center of the galaxy. How fast is the Sun moving with respect to the center of the galaxy?

    For this problem I took 2pi/T which gave me 2pi/192000000 and multiplied the result by 2x10^20m. I then expressed the answer in kilometers which gave me 6544984695km. This was not correct. Any suggestions?

    Thanks for your generous help!
    Last edited: Oct 4, 2007
  2. jcsd
  3. Oct 5, 2007 #2


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    The number you have is in units of km/year... are these the units you need?
  4. Oct 5, 2007 #3
    Yes - it was indeed a problem of units. I took 2pi/(195 million years)(second in a year) * 2.0x10^20 and came up with the correct answer once I converted centimeters into kilometers.

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