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Help me Please

  1. Nov 12, 2004 #1
    The earth has an orbit of radius 148 million km around the sun. What is the speed of the earth on this orbit?

    dont know how to do it i have used a couple of different formulas and havent gotten it right can anyone help?
  2. jcsd
  3. Nov 12, 2004 #2
    Can you not use v = rω and the fact that ω = 2π/T?
  4. Nov 12, 2004 #3


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    How long does the earth take to make an orbit around the sun?
    What distance does the earth travel in an orbit?
    (Since the problem tells you that the orbit has a radius you can probably safely approximate the orbit with a circle of the appropriate radius.)
    Then you can find speed using [tex]s=\frac{d}{t}[/tex] although you might want to do some unit conversion.
  5. Nov 12, 2004 #4
    Period T = 365 days = ... seconds.
    Then using formulae which Nylex gave.
  6. Nov 12, 2004 #5
    What is the speed of the earth on this orbit? 30km/s
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