If two spheres of same material and same radius r are touching each other, then show that the gravitational force between them is directly proportional to r^4

If two spheres of same material and same radius r are touching each ot

1.	If two spheres of same material and same radius r are touching each other, then show that the gravitational force between them is directly proportional to r^4
Answer» SOLUTION :`F = (Gm_(1) m_(2))/r^2` `=G/r^2 [(4/3pir^2rho)(4/3pir^2 rho)]` `=(4/9pi^2rho^2G)r^4` `:. F alphar^4`