What is the principle of inertial frames and non-inertial frames?

The principle of inertial frames states that the laws of physics are the same in all inertial frames.

Inertial frames are frames of reference in which an object at rest remains at rest and an object in motion moves with a constant velocity in a straight line. The principle of inertial frames states that the laws of physics are the same in all inertial frames. This means that if an experiment is conducted in one inertial frame, the same results will be obtained in any other inertial frame that is moving at a constant velocity relative to the first frame.

Non-inertial frames, on the other hand, are frames of reference that are accelerating or rotating. In these frames, objects appear to experience fictitious forces that are not present in an inertial frame. For example, if you are in a car that is accelerating, you feel a force pushing you back into your seat. This force is not present in an inertial frame and is therefore called a fictitious force.

The principle of inertial frames is important in physics because it allows us to make predictions about the behaviour of objects without having to consider the motion of the observer. By choosing an inertial frame as our reference frame, we can simplify our calculations and make accurate predictions about the behaviour of objects in motion.