- #1
Beholder
- 8
- 0
Hello I need some help understanding Newtons universal gravitation. I read on a site that an objects Force on Earth is its mass x gravity(on earth) hence MG (like F=MA). Then they say using Newtons inverse square law that the same object at a distance of the moon would have the force(g) MG/distance to moon² and so it would be that much weaker.
Now with the universal gravitation between two masses we know F=GxM1xM2/R²
my questions are how did Newton come to this conclusion?, what is the inverse square law?, and why are the two masses multiplied not added? I'm a little confused about this the only answer I can come up with is:
say we have the first equation they talked about F=MG (g for gravity on earth) if we substitute G with its components M x Gravitational constant we get two separate masses mass 1 for the object and mass 2 for the Earth and we also get G (grav. const.) so that's our GxM1xM2, now divide that by the square of the distance between them and we get the answer. Is that even close? can anyone answer where this equation comes from?