How is the oscillation amplitude indicated? How to find the amplitude?

Science 2023

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How is the oscillation amplitude indicated? How to find the amplitude?
How is the oscillation amplitude indicated? How to find the amplitude?

Starting from the seventh grade, schools begin to teach such a topic as "Mechanical vibrations". Starting from the OGE and ending with the Unified State Examination, this topic can be traced in many exams and entrance tests. An important part of it is the study of the concept of the amplitude of oscillations. Therefore, to begin with, let's get acquainted with what the amplitude of oscillations is and how the amplitude of oscillations is denoted in physics, because over time a lot is forgotten, and for some reason this variable is given the least attention in many schools.

What is the oscillation amplitude?

The amplitude of fluctuations is the maximum possible deviation or shift of a value up or down from the equilibrium position or from the average value. For example, for a spring pendulum, the equilibrium position is a load resting on a spring, and when it starts moving, it acquires a certain amplitude, which is determined by the tension or compression of the spring.

For a mathematical pendulum it is a bit simpler - the maximum deviation of the load from the rest position - this is the amplitude of oscillations.

Bwhile the amplitude of the oscillations of radio waves is calculated precisely by the deviation from the average value.

Now let's move on to what letter denotes the amplitude of oscillations.


In the seventh grade, children are taught to designate the amplitude of oscillations with a simple letter "A". For example: A=4 cm, that is, the amplitude is four centimeters.

But already in the eighth grade, students learn such a thing as mechanical work, and it is she who is denoted by the letter "A" in physics. Students begin to get confused in these values, and by the 10-11th grade they do not have a clear idea of ​​\u200b\u200bhow the amplitude of oscillations is indicated in physics.

In the case of spring and mathematical pendulums, it is best to write the amplitude in terms of maximum values. That is Xmax. means the maximum deviation from the equilibrium position. For example, Xmax.=10 cm, that is, the spring, as an option, will stretch a maximum of 10 cm. This will be the amplitude of oscillation.

In the 11th grade, graduates study electromagnetic oscillations. And there are fluctuations in charge, voltage and current strength. In order to record the voltage amplitude, it is customary to designate it as the maximum value. For charge and other quantities, respectively.

How to find the amplitude of fluctuations?

Swing Graph

Usually, in the problems of finding the amplitude, a graph is presented, similar to the one shown in the picture above. In this case, the amplitude will be the maximum value along the vertical Y-axis. The amplitude is shown as a red line.

For example, on thisThe figure shows a graph of the oscillations of a mathematical pendulum.

chart with numbers

Knowing that the amplitude of the oscillation of a mathematical pendulum is the maximum distance from the equilibrium position, we can determine that the maximum value of X=0.3 cm.

Find the amplitude using calculations in the following ways:

1. If the load performs harmonic oscillations and the path that the body passes and the number of oscillations are known in the problem, then the amplitude is found as the ratio of the path to the number of oscillations multiplied by 4.

2. If a mathematical pendulum is given in the problem, then with the known maximum speed and length of the thread, you can find the amplitude, which will be equal to the product of the maximum speed and the square root of the ratio of the length to the free fall acceleration. This formula is similar to the formula for the period of a mathematical pendulum.

period formula

Only maximum speed is used instead of 2p.

In equations, the amplitude is everything that is written before the cosine, sine or omega variable.


In this article, it was said how the amplitude of oscillations is indicated and how it is found. This topic is only a small part of a large section of oscillatory processes, but this does not reduce its importance. After all, without understanding what amplitude is, it is impossible to work with graphs correctly and solve equations.

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