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Kepler's planetary motion and inverse square law

  1. Mar 11, 2013 #1

    The inverse square law of Newton's gravitational force, is it somehow related to each other?

    I mean to say P^2 is directly prop.a^3. Is it from the third law that the derivation of inverse sq.law of G=M.m/R2 is derived?

  2. jcsd
  3. Mar 11, 2013 #2
    You can derive all of Kepler's laws from the inverse square law of gravitation.
  4. Mar 11, 2013 #3


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    Staff: Mentor

    Basically, yes. This old thread has a couple of links to files that have more details. See posts #9 and #10.

  5. Mar 12, 2013 #4
    But I think the second law is not only for inverse square rule, in fact it holds true for any centre field force([itex]\vec{F}= f(r)\vec{r}[/itex]) because [itex]\dot{S}= \frac{1}{2}r^2 \frac{dw}{dt}[/itex] where [itex]r^2 \frac{dw}{dt}[/itex] is consevative in any central force field.
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