Gravitation PDF

Gravitation is the force of attraction between any two objects in the universe. The universal law of gravitation states that the force of attraction between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The...

Gravitation is the force of attraction between any two objects in the universe. The universal law of gravitation states that the force of attraction between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The force of attraction is along the line joining the centers of the two objects. The value of the universal gravitational constant, G, is 6.673 x 10^-11 Nm^2/kg^2. G is a universal constant because its value does not depend on the nature of the intervening medium or temperature or any other physical variable. The universal law of gravitation successfully explains several phenomena, such as: * The force that binds us to the earth. * The motion of the moon around the earth. * The motion of planets around the sun. * The tides due to the moon and the sun. The force of gravity is the force of attraction between the earth and any object. The value of g, the acceleration due to gravity, is 9.8 m/s^2. The value of g decreases as we move away from the surface of the earth or go into a deep mine. The weight of an object is the force with which the earth attracts it. The weight of an object is equal to its mass times the acceleration due to gravity. The weight of an object on the moon is one-sixth of its weight on the earth. Thrust is the force acting perpendicularly on a surface. Pressure is the thrust acting per unit area. The SI unit of pressure is the pascal (Pa). Buoyancy is the upward force exerted by a fluid on an object immersed in it. Archimedes' principle states that the buoyant force acting on an object is equal to the weight of the fluid displaced by the object. Relative density is the ratio of the density of a substance to the density of water at 4°C.