# Law of inertia. Difficulties in explaining everyday phenomena

Some processes and phenomena that accompany usconstantly, about the nature and causes of which we do not even think, with a deeper examination may reveal an inexhaustible source of information about the laws and rules to which the entire physical world is subject.

It would seem that the general between the object, resting on the spot, and making a rectilinear uniform motion? The laws of motion were also of interest to the ancientthinkers. The "physics" of Aristotle, dating from the 4th century BC, contains the conclusions of the ancient Greek thinker about the nature of rest and movement. Practically following the right path in an attempt to explain this ordinary phenomenon, he makes a very interesting conclusion in his next work, "Mechanics." Aristotle completely abandoned the use of the concept of "absolute emptiness" and concluded that for any movement, a permanent effect on the subject of a certain force is necessary. He points out that with the cessation of the impact of force, the movement also ceases. Thus the thinker, being a step away from describing the law of inertia, followed the wrong path.

Two millennia took human thought,Aristotle's conclusions. The Italian physicist and philosopher, mechanic and astronomer Galileo Galilei found deficiencies in the interpretation of the nature of the movement adopted by the official science of that time. Galileo's law of inertia almost fully corresponds to the modern explanation, but its remarkableity lies in the fact that for its formulation and proof it was impossible to use the experimental base because of the absence of ideal conditions. This conclusion the Italian thinker carried out on the basis of personal observations, by following from the opposite and using the method of exclusion.

Thus, the law of inertia is practicallythe brainchild of Galileo, although it is used by modern science in the Cartesian treatment. Another merit of the great Italian is the indication that free movement is possible not only in a straight line, but also in a circle. In practice, this assumption made it possible to describe rotational motion by inertia. The law of conservation of the moment of inertia became a logical continuation of Galileo's conclusions.

Subsequently, the Englishman Isaac Newton created a wholesystem of laws of mechanics. He included the law of inertia in this system as the first. But science does not stand still - during the existence of the Newtonian system, it has repeatedly been criticized and attempts to revise the postulates laid down in it.

The twentieth century, which became a period of indigenousrevision of traditional laws under the influence of Einstein's discoveries, introduced certain amendments to the interpretation of the basic laws of mechanics. But for the practical use, engineering calculations and design of mechanical systems, the conclusions and formulas of traditional mechanics are still applied.

When we use the law of inertia in practice,When carrying out calculations, a number of assumptions must be made. It is almost impossible to achieve the existence of a full-fledged inertial system. Often, in calculations, it is easier to take the system as a non-inertial one, which makes it impossible to use Newton's laws. Considering an aggregate relative to the reference system for which we take the car itself, we can use the law of inertia as long as the machine is stationary, or evenly moving. With acceleration and braking, this reference frame completely loses its inertial properties.

You can give a lot of examples when you have tofor the purpose of obtaining a result in more simple ways to overlook factors, albeit those that matter, but do not have a significant effect on the final conclusions. Modern mechanics fully admit such liberties, although for more precise calculations it requires the consideration of certain factors due to the introduction of various coefficients and corrections.