CLASS: IX NCERT (CBSE)
Gravitation
SUMMARY
Freely falling object: Is the object which moves towards the Earth due to force of gravity
Acceleration due to gravity: It is the acceleration produced in an object due to force of gravity
Acceleration due to gravity varies from place to place
Acceleration due to gravity is zero at the centre of the Earth
Acceleration due to gravity is independent of the mass of the object
Newton’s third law of motion is applicable to force of gravitation
Mass is defined as the amount of matter contained in it
SI unit of mass is Kilogram
Mass remains constant throughout the universe
Mass of an object can never be equal to zero
Mass is a scalar quantity
Weight is the force with which an object is pulled towards the centre of the Earth
SI unit of weight is Newton
W= mg
Weight is a Vector quantity
Weight of an object can be equal to zero i.e., when g is equal to zero
Weight varies from place to place
1kg.Wt = 9.8 N
Projectile is an object thrown into space horizontally under the action of Earth’s gravity
Trajectory is the path followed by a projectile
