Galilean Relativity: Volume-3

Inertial Frames

Inertial Frame of Reference

    Physicists generally have a tendency to mention the frame of reference and its type, such as inertial or non-inertial. The importance of the frame of reference lies in the fact that the Law of Inertia is valid in it. Law of Inertia is also known by the name Newton's First Law of Motion which states that a body will tend to continue in its state of rest or uniform motion unless and until acted upon by an external force. Referring back to the cabin of ship described in Galilean Relativity: Volume-1 all the objects inside the cabin will follow the law of inertia till the time it is an inertial frame.

          An inertial frame is defined as a frame which is at rest or moves with a uniform velocity i.e. not gaining speed. Any reference frame with a constant relative velocity to an inertial frame is also considered as an inertial frame. A frame which is accelerating is known as an Accelerating Frame and consequently the law of inertia is not valid in it. When analyzing the behavior of an object in accelerating frame, the results seem to be absurd. To account for the acceleration of the frame a pseudo force is employed or simply an acceleration of same numerical value but in opposite direction. Similarly, the Galilean Relativity is implemented using inertial frames or using pseudo force or negative acceleration for accelerating frames.