Re: Knowing what you know not about what should be known

[John Clement <clement@HAL-PC.ORG>]

Mark's answer that it is the results from an experiment is quite adequate,
but if you want something else you might find understandable consider the
following.

A nucleon (neutron or proton) in mass 1 pulls on each nucleon in mass 2.
Therefore the force on the other mass is proportional to the number of
nucleons in mass 2 or the total mass in 2.  But the force must be multiplied
by the number of nucleons in mass 1 or by the mass of mass 1.  Hence the
force is proportional to m1 x m2.  The inverse square is actually more
mysterious to most people.  But this is explainable by the idea that the
field is spread out over an area so its strength decreases as the area
increases.

John M. Clement
Houston, TX

> We say the the force is the product of masses
>
> divided by the square of the distance between them,
>
> and it is readily understandable why we say the
>
> square of distance, since this is simply the falling
>
> off according to the inverse square. But, why do
>
> we say PRODUCT of masses? What is the physical
>
> cause of that?  If you know about that, I will be very grateful for your
> reply. Seriously, I have NEVER gotten a real explanation of this.