gravity force

[dudenexdoor1]

balaji.k from tirupur - 641602 phone no 919843053634

why is according 2 law of gravity the force between any two objects is inversely proportional to the square of the distance between them and not (say cube of the distance or to the fourth power

[Fred Flin]

If you imagine an expanding sphere from the centre of one of the masses. The flux (intensity) of the gravitational field is spread out over the surface of the sphere. Since the area of a sphere is (1/3 Pi r^2), as the radius increases the area the field is spread over decreases. So the strength of the field decreases by the same factor. ie. inverse square.