When studying the question of what is the force of inertia (SI), misunderstandings often occur, leading to pseudoscientific discoveries and paradoxes. Let's look at this issue by applying a scientific approach and justifying everything said by confirming formulas.
The force of inertia surrounds us everywhere. People noticed its manifestations in antiquity, but could not explain. Seriously, Galileo studied it, and then the famous Isaac Newton. It is because of its extensive interpretation that erroneous hypotheses became possible. This is quite natural, because the scientist made an assumption, and the luggage of knowledge accumulated by science in this area did not yet exist.
Newton argued that the natural property of all material objects is the ability to be in a state of uniform motion in a straight line or to rest, provided that there is no external influence.
Based on current knowledge, let us “expand” this assumption. Even Galileo Galilei drew attention to the fact that the force of inertia is directly related to gravity (attraction). And natural attracting objects, the effect of which is obvious - are planets and stars (due to their mass). And since they have the shape of a ball, then Galileo pointed to this. However, Newton completely ignored the moment.
It is now known that the entire Universe is permeated with gravitational lines of various intensities. Indirectly confirmed, although not mathematically proven, the existence of gravitational radiation. Therefore, the force of inertia always arises with the participation of gravity. Newton, in his assumption of a "natural property", did not take this into account either.
It is more correct to proceed from another definition - the indicated force is a vector quantity whose value is the product of the mass (m) of the moving body and its acceleration (a). The vector is directed opposite to acceleration, that is:
F = m * (- a),
where F, a are the values of the force vectors and the obtained acceleration; m is the mass of a moving body (or mathematical material point).
The most important point: it will be a mistake to consider that the acceleration itself is caused by force, as it might seem from the formula. That is why “-a” is written, but not “a” as a hint.
Physics and mechanics offer two names for this effect: Coriolis and the portable inertia force (PSI). Both terms are equivalent. The difference is that the first option is universally recognized and used in the course of mechanics. In other words, the equality holds:
F kor = F per = m * (- a kor) = m * (- a per),
where F is the Coriolis force; F per - portable inertia force; a kor and a per are the corresponding acceleration vectors.
PSI includes three components: centrifugal inertia, translational SI and rotational. If there are usually no difficulties with the first, the other two require explanation. The translational inertia is determined by the acceleration of the whole system as a whole relative to any inertial system with a translational type of motion. Accordingly, the third component arises due to the acceleration that appears when the body rotates. At the same time, these three forces can exist independently, not being part of the PSI. All of them are represented by the same basic formula F = m * a, and the differences are only in the type of acceleration, which, in turn, depends on the type of motion. Thus, they are a special case of Coriolis inertia. Each of them participates in the calculation of the theoretical absolute acceleration of the material body (point) in a fixed reference system (invisible to observation from a non-inertial system).
PSI is necessary when studying the issue of relative motion, since in order to create formulas for the motion of a body in a non-inertial system, it is necessary to take into account not only other known forces, but also its (F kor or F per).