Inertiaaliviitekehys

Inertiaaliviitekehys, often translated as inertial frame of reference, is a fundamental concept in physics. It refers to a reference frame in which Newton's first law of motion, the law of inertia, holds true. This means that an object at rest will remain at rest, and an object in motion will continue in motion with constant velocity, unless acted upon by a net external force. In simpler terms, an inertial frame is one that is not accelerating.

Examples of inertial frames include a stationary observer on Earth or a spaceship moving at a constant velocity through deep space, far from any significant gravitational influences. In contrast, a non-inertial frame is one that is accelerating. For instance, a rotating merry-go-round or a car suddenly braking are examples of non-inertial frames. In these accelerating frames, objects can appear to experience fictitious forces, such as centrifugal force or Coriolis force, which are not due to actual physical interactions but rather the acceleration of the frame itself.

The concept of inertial frames is crucial for understanding classical mechanics. While the laws of physics are the same in all inertial frames, they are not the same in non-inertial frames without the introduction of these fictitious forces. The principle of relativity, as formulated by Galileo and later extended by Einstein, states that the laws of physics are invariant under transformations between inertial frames. This means that no experiment can distinguish one inertial frame from another.