rizal23

I have some questions regarding the gravitational constant and Newton's theory of gravity. To start, I am a first year physics undergrad student just so you have a sense of my caliber of understanding. Here is my question. As I understand Newton was able to come up with an equation for the gravitational force of attraction between any two massive bodies F= (M1*m2)/d^2

Later, Henry Cavendish invented an experiment in order to find the gravitational constant (6.673 * 10^-11 kg^-1*m^3*s^-2), originally intended to find the density of Earth, which happened a number of years after Newton's death. Cavendish's constant was about 1% off the number we use today. What I'm trying to understand is what is the purpose behind the constant or proportionality. Why is the gravitational constant even necessary, especially if Newton was already able to derive the original equation for the force of gravity between any two massive bodies without this constant? What I'm mostly looking for is a better understanding for constants of proportionality. mu_0 (permeability constant in magnetic field equation) is also an example of a constant I'm still having trouble understanding the purpose of. I simply am having trouble understanding why the main variables involved in these processes simply aren't enough to satisfy their respective equations, why is a proportionality constant so necessary?

Formula of the gravitational force is F = (G * M₁ * m₂)/R²

info:

G : gravitational constant

M₁ : active gravitational mass of body 1

m₂ : passive gravitational mass of body 2

R : the radius of the object

vBulletin Community Forum