Dear student This law is applicable only if the following Conditions are met.. 1 - Two Bodies having Mass 2 - There must be Some Distance between them According to Universal Gravitional Law : (i)The Gravitional force Between two bodies having mass m1 and m2 directly depends on the product of their masses and (ii) Inversely Proportional to the Square of distance between them... F = Gravitional force m1 and m2 are the masses of bodies r = Distance between the bodies having masses m1 and m2... Now from statement (i) and (ii) we must have F = G m1 x m2 / r^2 ----(iii) where G is the constant of proportionality..called Universal gravitional Constant..... According to relation (iii)..if mass of the body increases then F will increase too...and decreases if the distance between them increase Regards