9th Class Science Gravitation and Floatation Introduction

       Introduction

In this chapter we shall study about gravitation and universal law of gravitation. We will discuss about the motion of the body under the influence of gravitation. How the weight of the body varies from one place to another? It was Sir Isaac Newton who first gave the term gravitation when he saw an apple falling from a tree and thought that 'why an apple fall towards the earth and not going otherwise'. Later he realized that it is because earth attracts every object towards itself with a force called the gravitational force. Later on the generalized the idea and said that not only the earth, but every other object in this universe attract each other with a force. Our knowledge about gravitation did not develop only as a result of Newton's observation of a falling apple. Before Newton there were many scholars who had been using the term Gurutva akarshan in India. Before Newton many scientist such as Aryabhatta and Kepler studied about the motion of the planet. It was Kepler who described 'how the planet moves around the sun?'.

Newton's laws of motion helps us to understand about the force which cause a planet's motion..