Question

State the universal law of gravitation.

Answer 1

Hint: The universal law of gravitation is about the gravitational force of attraction between two massive objects. The concept came from the idea that any object above the surface of earth always falls downward. This means that a force from earth always acts on the objects. Which gives the first idea of gravitational force.

Complete step by step answer:
Newton’s law of gravitation is about the gravitational force between two massive objects. The universal law of gravitation not only gives the gravity of earth, but it gives the universality of the law. We can apply it to any object in the universe.
Newton's law of gravitation gives the force of attraction between two objects at a distance apart.
Consider two massive objects of mass m and M are at distance R apart. Newton’s universal law of gravitation gives that the gravitational force of attraction between the two objects is directly proportional to the product of the mass of the two objects and inversely proportional to the square of the distance between them.
Mathematically we can express it as,
$F_g\propto {\displaystyle \frac{Mm}{R^2}}$
We can equate the above equation by introducing a proportionality constant G.
$$F_g={\displaystyle \frac{GMm}{R^2}}$$
Where G is the universal gravitational constant with its value $G=6.67\times {10}^{-11}N{m}^{2}k{g}^{-2}$ .
G is a universal constant with its value the same in all conditions.

Note: Gravity is a universal force which acts in the largest of the distances. But if we consider very small distances gravity does not work. This is because at very small distances strong force, weak force and electromagnetic forces are very strong and gravitational force is not strong enough to overcome these forces.