Dne 21/01/2018 v 03:08 Peter Riedt napsal(a):
Riedt's Fc=Fg, a=Fc/mpl and mpl=Fg/a
The Centripetal force discovered by Huygens in 1659 is Fc = mpl*v^2/r.
The Gravitational force, after Cavendish discovered in 1798
the gravitational constant G, is Fg=G*(M*m/r^2).
The second law of motion ascribed to Newton is F = ma, a=F/m, m=F/a.
The nine major solar planets connect the different formulas of Huygens,
Cavendish and Newton by Fc=Fg; a=Fc/mpl and mpl=Fg/a:
The radii applicable to the centripetal force formula
for an ellipses lay of the ellipse evolute,
seen as the red curve on the Wolframalpha article page.
http://mathworld.wolfram.com/EllipseEvolute.html
or on this animated GIF
https://en.wikipedia.org/wiki/Evolut...an_ellipse.gif
An evolute of a curve is the set of the curvature centres of the curve.
For a circle, the evolute degenerates into a point, the circle centre.
--
Poutnik ( The Pilgrim, Der Wanderer )
A wise man guards words he says,
as they say about him more,
than he says about the subject.