Mai Aour Mera Desh

Introduction |
Gravitation
Conten   * Universal law of gravitation   * Kepler's law   * Acceleration due to gravity   * Mass, Weight   * Thrust, Pressure   * Pressure in fluid   * Buoyancy or Upthrust   * Archimedes's principle   * Density    * We always feel that an object dropped from a height falls towards the earth. We known that all the planets go around the sun. the moon goes around the earth. In all the situation, there must be some force acting on the objects, the planets and moon. Isaac Newton given that the same force is responsible for all these. This force is known as gravitational force. We are going to study about gravitation in details.Universal law of gravitationEvery object in the universe attracts every other object with a force which is proportional to the square & inversely proportional to the square of the distance between them. This is called gravitation force & given by the formula F = G- ( i ) Here 'M' and 'm' is the mass of two objects A and B are separated distance 'd' from each other as shown in fig and G is called Universal gravitation constant

Also, G = - ( ii ) The SI unit of gravitation constant is Nm2kg-2and the accepted value is 6.673 *10-11
Nm2 kg -2
Note: Gravitational force always along the line joining the centries of two objects.    * Kepler's law Johannes Kepler de three laws, which are related to the motion of planets. These laws given as   1. The orbit is a planet is an ellipse with the sun at one of the foci as shown in fig (2). Here o is the position of the sun.Figure 2 Sun of one of the foci ––    2. The line joining the planet and the sun sweeps equal areas in equal intervals of time.   3. The cube of the mean distance of the planet from the sun is proportional to the sugar of its orbital period T.or= constant    * Acceleration due to gravity is acceleration due to the gravitational force of earth. It is represented by ' g' and unit of it same as that of acceleration i.e. (ms -2 ),.   * By second law of...