Inertial Frame

Non-Interial Frames:

(or accelerating frames)

A non-inertial frame of reference is a coordinate system in which Newton's first law of motion does not hold because the frame itself is undergoing acceleration. In other words, an object not subjected to external forces may appear to accelerate in a non-inertial frame due to the motion of the frame itself.

In an inertial frame of reference, an object at rest remains at rest, and an object in uniform motion continues in a straight line at a constant speed, as described by Newton's first law. However, when we consider a frame that is accelerating or rotating, additional apparent forces (pseudo or fictitious forces) may appear in the equations of motion.

Examples of non-inertial frames include a car making a turn, an elevator accelerating upward or downward, or a rotating platform. In such frames, forces like the centrifugal force or the Coriolis force may need to be introduced to explain the observed motion of objects, even though no actual physical forces are acting on them.

In contrast, an inertial frame of reference is a coordinate system in which an object subject only to its own inertia or external forces (like gravity) moves in a straight line at constant speed, as described by Newton's laws of motion.