It is assumed that space is continuous and the motion of particles in space can be described by their position at different instants of time. The position of a particle is known as a point in space. These points are described by the coordinate system in space. When point (position of particle in space) and the time are taken together then it is called an Event . The coordinate system of a particle which describe the position of any particle relative to it, then such coordinate system is known as Frame of Reference or System of Reference . Absolute Space: The absolute space is those frame of reference relative to which every motion and position should be measured. Types of Frame of Reference: According to the motion of particles frame of reference is divided into two categories Inertial frame of reference Non-inertial frame of reference Inertial frame of reference:

(The Advance Learning Institute of Physics and Technology)