viitekehyset

viitekehyset is a Finnish term that translates to "reference frames" in English. In physics, a reference frame is a set of coordinates used to describe the position, orientation, and motion of an object. It is a fundamental concept in classical and relativistic mechanics, as well as in other fields of science that involve the study of motion and space.

There are different types of reference frames, broadly categorized as inertial and non-inertial. An inertial reference frame is one in which an object at rest stays at rest and an object in motion continues in motion with constant velocity, unless acted upon by a force. This is in accordance with Newton's first law of motion. In contrast, a non-inertial reference frame is one that is accelerating. In such frames, fictitious forces, like the centrifugal force or Coriolis force, appear to act on objects.

The choice of reference frame is crucial for simplifying the analysis of physical phenomena. For example, describing the motion of a planet around the Sun is much simpler in a reference frame that is centered on the Sun and does not rotate. However, for some problems, such as analyzing the motion of objects on a rotating platform, a non-inertial frame might be more convenient, even with the introduction of fictitious forces.

The concept of reference frames is also central to Einstein's theory of relativity. Special relativity deals with inertial reference frames and the constancy of the speed of light, leading to concepts like time dilation and length contraction. General relativity extends this by considering accelerated reference frames and their equivalence to gravitational fields. The term viitekehyset encompasses all these contexts within the Finnish scientific and academic discourse.