Universal Law of Gravitation
As per the universal law of gravitation, if there are two objects A and B with masses 𝑚1 and
𝑚2, separated by a distance ‘d’, then the gravitational force between them is given by the following formula:
𝑭 = 𝑮
(𝒎𝟏 × 𝒎𝟐)/𝒅𝟐
where G is the universal gravitational constant.
Example – Universal Law of Gravitation
Consider a case where you are sitting in front of your computer. Now, both you and the computer will exert a pulling force on each other but still neither of the two moves towards each other.
This is because there are other forces acting on you and the computer. For example, the gravitational force of the Earth is pulling you as well as the computer strongly towards itself. As a result, the force between you and the computer becomes negligible compared to it.
There is also a force of friction that is much more than the gravitational force between you and the computer.
Forces Acting on Two Objects
We can also understand that the gravitational force between you and the computer is very weak by looking at the formula of gravitational force.
𝑭 = 𝑮 (𝒎𝟏×𝒎𝟐)/𝒅𝟐
where 𝑮 = 𝟔. 𝟔𝟕𝟑 × 𝟏𝟎−𝟏𝟏𝑵 𝒎𝟐 𝒌𝒈−𝟐
The value of G, that is the gravitational constant is very very small, and also the masses of the two objects are not big enough. Thus, the overall value of the gravitational force acting between the two is negligible.
Moreover, if we consider the gravitational force between you and the Earth or the computer and the Earth, then one of the masses will be the mass of the Earth, which is massive as compared to the other two masses. Therefore, the gravitational force pulling you and the computer down is much bigger than the force pulling you two towards each other.
Comparison of Gravitational Forces