The strength of air resistance - and without it in any way

We are so used to being surroundedair, which often do not pay attention to it. Here we are talking, first of all, on applied technical problems, in solving which, at first, it is forgotten that there is an air resistance force.

She reminds herself of herself for almost anyaction. Although we will go by car, even if we fly by plane, even if we just throw a stone. So let's try to understand what the force of air resistance is in the case of simple cases.

Have you ever wondered why cars have such astreamlined shape and a flat surface? But everything is really very clear. The strength of air resistance is composed of two values ​​- from the resistance of friction to the surface of the body and resistance to the shape of the body. In order to reduce the frictional force and achieve a reduction in roughness and roughness on the external parts in the manufacture of cars and any other vehicles.

To do this, they are primed, stained, polished andvarnished. Such processing of parts leads to the fact that the air resistance affecting the car decreases, the speed of the car increases and the fuel consumption decreases when driving. The presence of a drag force is explained by the fact that when the car moves the air is compressed and a region of local increased pressure is created in front of it, and behind it, respectively, the rarefaction region.

It should be noted that at higher speedsmachine movement, the main contribution to the resistance is made by the auto form. The strength of resistance, the formula for calculating which is given below, determines the factors on which it depends.

Resistance force = Cx * S * V2 * r / 2

where S is the area of ​​the front projection of the machine;

Cx is a coefficient that takes into account aerodynamic resistance;

V is the speed of motion;

r is the density of air.

As is easily seen from the above formula,The resistance force does not depend on the mass of the car. The main contribution is made by two components - the square of the speed and the shape of the car. Those. with an increase in the speed of movement twice the resistance increases fourfold. Well, the cross section of the car has a significant impact. The more streamlined the car is, the less air resistance.

And in the formula there is another parameter, which is simplyrequires paying close attention to it - the density of the air. But its influence is more noticeable when flying planes. As is known, the air density decreases with increasing altitude. Hence, accordingly, the strength of his resistance will decrease. However, for the aircraft, the same factors, like speed and shape, will still influence the amount of resistance applied.

No less curious is the history of the studyInfluence of air on accuracy of shooting. Works of this nature have been conducted for a long time, their first descriptions refer to 1742. The experiments were conducted in different countries, with different forms of bullets and shells. As a result of the research, the optimal shape of the bullet and the ratio of its head and tail parts were determined, and ballistic behavior tables of the bullet in flight were developed.

Further studies of the dependencethe bullet fired from its speed, the form of the bullet continued to be tested, and the research methodology was improved. Mathematical models were developed and a special mathematical tool was created-the ballistic coefficient. It shows the ratio of the forces of aerodynamic drag and inertia forces acting on the bullet.

The article considers what constitutes forceresistance of air, a formula is given that allows to determine the magnitude and degree of influence of various factors on the resistance value, its effect in different fields of technology is considered.