CBSE Class 9 Physics Gravitation
Universal Law of Gravitation
The force with which the two objects attract each other is called gravitational force.
Gravitational force of the earth on a body is known as gravity.
Universal law of gravitation: Every body in the universe attracts every other body with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Acceleration with which a body falls towards the centre of the earth is called acceleration due to gravity.Thrust and Pressure
Mass is the quantity of matter contained in the body and weight is the force with which the earth attracts the body.
Mass of a body does not change but weight of a body is different at different places.
The force acting on a body perpendicular to its surface is called thrust.
The force acting on a unit area of the object is known as pressure.Archimedes' Principle
Archimedes' Principle