To answer the question of which oscillations are called harmonic, it should be borne in mind that these physical phenomena are one of the most common in nature. It is perhaps difficult to indicate a sphere where harmonic oscillations are not present. The most common areas of physical theory in which oscillatory processes are studied are mechanics, electrical engineering and electronics, radar and sonar, and others.
All these regions are combined without exception in that the nature of the oscillatory processes is, as a rule, the same, and therefore there is a general classical theory for their description. The parametric differences in the oscillatory processes are due only to the environment of their occurrence and external factors that can affect the vibrational movements. The simplest example of vibrational movements that we daily encounter in everyday life are, for example, the oscillations of the pendulum of a clock, or electric current.
Oscillations by the nature of their course are free and harmonic. Free vibrations are also called intrinsic vibrations , this emphasizes that they, as their source, have external perturbations of the medium, which bring the physical body out of static equilibrium. An example is the weight, which is suspended on a thread, and to which we push set some kind of oscillatory process.
A more significant place in physical theory is given to the study of such a phenomenon as harmonic vibrations. Studying their nature just forms the theoretical basis on which the study of narrower aspects of oscillatory processes is based, namely, their course in various media - mechanics, electricity, in chemical transformations and reactions.
In order to describe harmonic vibrations in physics, basic parameters such as period and frequency are used.
Based on the statement that we formulated earlier that there is a certain general universal model of the course of oscillatory processes, we can logically come to the conclusion that there are some universal quantities characterizing these oscillations. Therefore, the mentioned parameters โ period and frequency โ are characteristic of all types of oscillations, regardless of the source of their generation and the medium of their course.
The frequency is a quantitative value that shows how many times during a certain period of time, the physical body has completed the process of changing its static state and returned to it. So, for example, you can calculate how many times, the same sinker hesitated after we pushed him until he stopped completely.
The period in this process will show the time period for which this weight deviates from its original position and returns to its original position in one swing.
Studying harmonic vibrations, it should be understood that the period and frequency are objectively related by a general formula, which ultimately determines the schedule of harmonic vibrations. To understand in more detail what it is, it should be noted that there are other parametric indicators - amplitude, phase, cyclic frequency. Their use allows us to use trigonometric functions to describe oscillatory processes. The most common formula for plotting is the following: s = A sin (ฯt + ฮฑ). This formula, also called the equation of harmonic oscillations, allows you to build a graph of the oscillatory process, which in its simplest form is an ordinary sinusoid. In the given example of the formula, the coefficients ฯ and ฮฑ show exactly which transformations must be performed with a sinusoid in order to display a specific oscillatory process.
With more complex oscillatory phenomena, their graphical description is naturally complicated. This complication is associated with two main factors:
- the nature of the process, that is, by what particular vibrations are being studied - mechanical, electromagnetic, cyclic or other;
- the environment in which oscillatory phenomena are generated and carried out - air, water or otherwise.
These factors significantly affect all parameters of any oscillatory process.