What happens to the force between two objects, if
(i) the mass of one object is doubled ?
(ii) the distance between the two objects is doubled ?
(iii) the distance between the two objects is tripled ?
(iv) the masses of both the objects are doubled?

Explanation

The force of attraction between two objects is `F=G (Mm)/d^(2)`.
(1) When a mass of one object is doubled.
`F.=G (2Mm)/(d^(2))`
`=2 xx G (Mm)/(d^(2))=2F`
The force is doubled
(ii) When the distance is doubled.
`F.=G (Mm)/((2d)^(2)) `
`=1/4 G (Mm)/d^(2)=1/4 F`
The force becomes `1/4th`.
(iii) When the distance is tripled.
`F.=G (Mm)/((3d)^(2))`
`1/9 G (Mm)/(d^(2))`
`=1/9F`
The force becomes `1/9th`.
(iv) When the masses of both the objects are doubled.
`F.=G (2M xx 2m)/(d^(2))=4G (Mm)/(d^(2))=4F`
The force becomes four fold.