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Homework Help: Physics Help : gravitational field

  1. Oct 27, 2004 #1
    Two stars, masses 10^20kg and 2* 10^20kg respectively, rotate about their common centre of mass with an angular speed of w. Assuming that the only force on a star is the mutual gravitational force between then, calculate w.
    Distance = 10^6km and that G= 6.7*10^-11Nm^2/kg^2
  2. jcsd
  3. Oct 27, 2004 #2
    Find out the location of center of mass. Let it be [tex]r[/tex] away from one of the stars.

    Then use
    [tex] \frac{G \mu m}{r^2} = mr \omega^2 [/tex]

    where r is the reduced mass of the two stars.

    [tex]\mu=\frac{Mm}{M+m} [/tex]

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