Question

The gravitational force between two objects is 200 N when they are at a distance of 5m. Find the gravitational force between them when they are at a distance of 250 cm

Answer 1

$$F=G\frac{mM}{r^2}\\F'=G\frac{mM}{r'^2}=F\frac{r^2}{r'^2} \\F'=200\frac{5^2}{2.5^2}=800\ N$$