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Keplers laws deduced from newtons law of gravitation watch

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    Can someone give a link for this, or give a proof?



    thanks
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    F= G Mm / ( r^2)

    F=mv^2 / d

    Speed = dinstance / time


    U basicaully have to combine those three eqations because you can think of the force as a gravitational force and a centripetal force and it leads to keplers laws
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    (Original post by kingmonkeywoman)
    F= G Mm / ( r^2)

    F=mv^2 / d

    Speed = dinstance / time


    U basicaully have to combine those three eqations because you can think of the force as a gravitational force and a centripetal force and it leads to keplers laws

    yeah, but is that the only law that can be deduced?

    cant the 1st and 2nd law?
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    wouldn't u just equate F=GMm/r^2 and F=mv^2/r ???

    using: v= angular velocity X r

    and: angular velocity = 2 pi / T
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    (Original post by Mathemagician)
    yeah, but is that the only law that can be deduced?

    cant the 1st and 2nd law?

    Erm, i dunno, i dont think they can no.

    I mean how can u use it to show the orbit in an ellipse when u have to assume its a circle to prove his third law....

    This kepler just came up with it because he couldnt fit mars into a circular orbit even when he used epicycles


    So u dont think you can prove the other three laws, but maybe u can in some complicated way i dont know about, you definately dont need to know about that for cosmology exam though
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    ok in free fall mv^2/r=GMm/r^2
    so V^2/r=GM/r^2
    V^2/r=w^2r
    but w=2pi/T
    so (2pi/T)^2 x r=GM/r^2
    so thus 4(pi)^2 r^3=GMT^2
    so 4pi^2/GM=T^2
    so
 
 
 
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