Let 𝑀𝐸 be the mass of the Earth and m be the mass of an object on its surface. If R is the radius of the Earth, then according to the universal law of gravitation, the gravitational force (F) acting between the Earth and the object is given by the relation:
𝐹 = {𝐺𝑀_𝐸𝑚 \over 𝑅^2}