Question

How does the force of gravitation between two objects change when the distance between them is reduced to half?

Answer 1

According to the universal law of gravitation,

$F=G\frac{Mm}{r^2}$

As the distance between objects is reduced to half, therefore,

r' = r/2

$F=G\frac{Mm}{(\frac{r}{2}{)}^2}=4\times G\frac{Mm}{r^2}=4F$

Thus, the force of gravitation increases by a factor of 4.