Answer:
it is 1 / square root of the change in distance
Step-by-step explanation:
since the equation of the gravitational force is
then F and r are inversely related, by the equation
this means when F is multiplied by 2 then r^2 is multiplied by half
so when r is multiples by half we first square the number (0.5) ^ 2 = 0.25
so
which means F is multiples by 1/0.25 or 4 when the radius is halfed