9th Class Science Gravitation and Floatation Universal Law of Gravitation

        Universal Law of Gravitation

According to universal law of gravitation, every two object in this universe attracts each other with a force, which is directly proportional to the product of their masses and inversely proportional to the square of distance between them.

Let us consider two object of mass \[{{M}_{1}}\] and \[{{M}_{2}}\] and d be the distance between their centre. If F be the force between the two object, then

                \[F\,\alpha {{M}_{1}}\times {{M}_{2}}\] and \[F\,\alpha \,\frac{1}{{{d}^{2}}}\]

Combining the above two equation we get,

\[F\,\alpha \,\frac{{{M}_{1}}\times {{M}_{2}}}{{{d}^{2}}}\]

                Or,          \[F=G\,\frac{{{M}_{1}}\times {{M}_{2}}}{{{d}^{2}}}\]

                Where, G is universal gravitational constant.

The value of G is found to be \[\mathbf{6}\mathbf{.67\times 1}{{\mathbf{0}}^{\mathbf{-11}}}\mathbf{N}{{\mathbf{m}}^{\mathbf{2}}}\mathbf{/k}{{\mathbf{g}}^{\mathbf{2}}}\]. The value of G is called universal constant i.e. it remains same everywhere in this universe. It does not depend on anything. It is applicable for all particle whether small or large.