Definition: Gravitation
"Every particle of matter in the universe attracts every other particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The direction of the force is along the line joining the particles."
or
The force by which the Earth attracts objects towards its centre is called gravitational force.
Define the gravitational field.
The gravitational field intensity `vec"E"_1` at a point is defined as the gravitational force experienced by unit mass at that point.
Define gravitational potential energy.
Potential energy of a body at a point in a gravitational field is the work done by an external agent in moving the body from infinity to that point.
Define gravitational potential.
The gravitational potential is defined as the amount of work required to bring unit mass from infinity to that point.
The weight is defined as the downward force whose magnitude ‘w ’ is equal to that of upward force that must be applied to the object to hold it at rest or at constant velocity relative to the Earth.