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Could someone explain this image to me?

  1. Mar 13, 2013 #1
  2. jcsd
  3. Mar 13, 2013 #2
  4. Mar 13, 2013 #3
    Throw us a bone... What part do you understand?
  5. Mar 13, 2013 #4
  6. Mar 13, 2013 #5
  7. Mar 13, 2013 #6


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    Where does that Wiki article fall short? It seems to have it all there. Or you could try this link, possibly. The formula (for a circular orbit) is arrived at by equating the gravitational force at a distance r and the force needed for a circular orbit at that distance.
    For a general Elliptical orbit is is more complicated but Kepler's law might do for you (he based it on observation but didn't have access to Newton's law of gravitation at the time afaik).
  8. Mar 13, 2013 #7
    It doesn't. Maybe "helps" was the wrong way to put it. It filled in the blanks for me. The second one is what I'm having more trouble understanding.
  9. Mar 13, 2013 #8
    Oh, and thank you for the responses. Greatly appreciated.
  10. Mar 14, 2013 #9


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    This all depends on your level of Maths, I think. What Maths are you happy with- algebra, calculus?
    How about this link?
  11. Mar 14, 2013 #10


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    Staff: Mentor

    In the last line, "minutes" and "days" are missing as units, otherwise the equation is wrong.
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