gravitational force between two objects is given as
F = G m₁ m₂/r²
where m₁ = mass of first object , m₂ = mass of second object , r = distance between the two objects .
Initial case :
m₁ = m₂ = m
gravitational force between the objects is given as
F = G m²/r²
Final Case :
m₁ = m₂ = 3 m
new gravitational force between the objects is given as
F' = G (3m)²/r²
F' = 9 G m²/r²
F' = 9 F
hence the gravitational force between the two objects becomes 9 times.
