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Homework Help: Gravity of the sun

  1. Oct 17, 2004 #1
    What is the acceleration due to gravity of the sun at the distance of the earth's orbit?

    i have no idea where to begin.
  2. jcsd
  3. Oct 17, 2004 #2


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    The gravitational pull of the Sun on the Earth is the centripetal force keeping the Earth from flying off into the great beyond.
  4. Oct 17, 2004 #3
    Find the mass of the sun, and the distance between the sun and the earth. Then, think about Newton's Law of Universal Gravitation.
  5. Oct 17, 2004 #4
    This is what i obtained
    Sun's Mass: 1.99x10^30 kg,
    earth-sun distance: 150x10^6 km.

    law of gravitional = Gm/r^2

    ((6.67*10^(-11)) * (1.99*10^30))/ (2.25*10^12)

    is that right?
    Last edited: Oct 17, 2004
  6. Oct 17, 2004 #5


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    Probably the simplest and most direct approach is to use Newton's law of gravity.

    Do you know what that is?
  7. Oct 17, 2004 #6
    law of gravity = Gm/r^2

    ((6.67*10^(-11)) * (1.99*10^30))/ (2.25*10^12)
  8. Oct 17, 2004 #7


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    The acceleration due to the Sun's gravity at the location of the Earth is just

    [tex]a = \frac {v^2}{R}[/tex]

    where v is the speed of the Earth around the Sun and R is the radius of Earth's orbit. You know R and you know the Earth travels a distance of [itex]2\pi R[/itex] in one year so you know its speed too.
  9. Oct 18, 2004 #8
    That should be right!
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