Answer:
Drop by a factor of 64
Explanation:
By Newtons law of gravity,
where;
G = Universal gravitaional constant
r = distance between center of gravities of two objects
m₁,m₂ = masses of thee objects.
F = Gravitational force.
m =
(mass = volume into density.
So when radius is halved, mass drops by a factor of 8,
m' = 
=
So in substitution to the equation,

