GRAVITATION

Gravity, we all experience it, pulling us towards earth constantly. But how does earth pull us all towards itself? It does not have arms, so what is it that earth uses to pull us downwards? We will try and find answers to these questions in this article.

Well gravity as we all know is a force that earth exerts on us to attract it towards itself. Well gravity is actually not exclusive to earth, any two objects which have mass attract each other with some amount of gravitational force. Yes, that’s true. Two fingers of ours, yourself and someone else, your wardrobe and your chair all of them, attract each other with gravitational force. So after knowing that now comes the question, then why doesn’t your chair and cupboard move towards each other? The answer is — the force of attraction between them is very small for them to move from their place and it is just not large enough to overcome friction which exists between the chair and the floor, but the force exerted by earth is very large and thus we experience it so strongly. But why is it that the earth exerts such a large amount of force on us but other objects don’t? The answer to this is — because of mass. The gravitational force is directly proportional to the masses of the objects and inversely proportional to the square of the distances between them. This means that more the mass of the two objects more strongly they attract each other and the less the distance between them the more they attract each other. This observation was also made by none other than the great Isaac Newton. This is perhaps one of his most important contribution to physics and the world. He has devised a relation between the gravitational forces between two objects, their masses and the distances between them. It is as follows:-

This expression is called as the “The Universal Law of Gravitation”. That “G” is known as the universal constant of gravitation or Newton’s constant. Its value is 6.67 times 10 to the power -11 newton-meter squared per kg squared. This formula can be used to calculate the force of gravitation between any two objects no matter how small or large. Please know that the two m’s in the equation are the masses and not the weights. The difference between the mass and the weight you ask? Well, that’s a topic for another article.