Verified answer

First answerer right ... there is no change in the Force.

Force = ma, and the masses of the objects do not change, neither does the acceleration!

It doesn't change because the same force is acting on the two bodies. If you're looking at instant force though, it would decrease fourfold because the force is dissipated into a longer time span

it decreases the amount of force by a factor of 4

think of impulse: F(delta t) = change in momentum

the amount of force needed to change momentum by an amount delta(mv) is delta(mv)/delta(t)

increase delta(t) by a factor of 4 and F decreases by the same factor