Answer
(a) $F=3.3\times 10^{-9}N$
(b) We know that $F$ and $r$ are inversely proportional, so if the side lengths are doubled, then the gravitational force will be decreased four times.
Work Step by Step
(a) As $F=2\times G\frac{m^2}{r^2}cos30^{\circ}$
We plug in the known values to obtain:
$F=2(6.67\times 10^{-11})\frac{(6.75)^2}{(1.25)^2}cos30^{\circ}$
$F=3.3\times 10^{-9}N$
(b) We know that $F$ and $r$ are inversely proportional, so if the side lengths are doubled, then the gravitational force will be decreased four times.
