Question 110677
According to the definition of inverse variation, we can say that "as one quantity increases, the other quantity decreases". 

example: "You got a job stuffing envelopes. So, the more time you work, the less envelope you have left to stuff".



Newton's Force of Gravity Equation (The Universal Gravity Equation is:
{{{F = GMm/R^2)}}} involves both direct and inverse variation. Mathematically, G is the constant of variation or the universal gravitational constant.

1. {{{Force}}} and product of {{{masses}}} vary {{{directly}}}. If the mass product increases, then the force between the centers of the two masses also increases by the same factor, and vice versa, (when the distance is unchanged.) 

you need this part:


2. {{{Force}}} and {{{square_ of_ distance}}} vary {{{inversely}}}. 

If the {{{distance_ between_ the _centers_ of _the_ two_ masses_ increases}}}, the {{{force}}} of gravity between two objects {{{decreases_ by _the _same_ factor}}}, and if the {{{distance_ between_ the _centers_ of _the_ two_ masses_ decreases}}},  (when the masses are unchanged.)

So, if each of their masses is tripled but the {{{distance_ between_ the _centers_ of _the_ two_ masses_ cut _to _one-third
}}}, then the {{{force}}} will be {{{9}}} times greater.