Sound and Oscillation

# mechanical resonance

Mechanical resonance occurs when a body is subjected to energy pulses with a frequency equal to one of its natural frequencies, causing an increase in its amplitude.

Mechanical resonance occurs when a body receives energy pulses with a frequency equal to one of its natural frequencies of vibration. This causes it to have increasing amplitudes, as the system stores energy.

All physical systems have one or more natural frequencies of vibration. If a system receives energy pulses with a frequency equal to one of its natural frequencies, it will begin to vibrate with increasing frequencies.

We can produce mechanical resonance when pushing a swing if the frequency of the periodic pushes is the same as the natural frequency of the swing. Thus, the balance can execute the movement with increasing amplitudes, reaching a greater height.

To better understand the resonance, look at the figures below, where the waves describe the movement of the swing given as an example:

This figure depicts the natural movement of the swing before receiving energy pulses.

When pushed, there is an increase in the amplitude of the swing oscillations, the new movement being described by the graph:

Comparing the two figures, we see that there is an increase in the amplitude of the wave

The amplitude of the wave will be given by the superposition of waves , that is, by the sum between the amplitude of the previous wave and the amplitude of the energetic wave that caused the resonance.

Mechanical resonance has already caused many disasters and destruction. One of them was the Tacoma Bridge fall, where the natural frequency of this wave was equal to the frequency of the wind at the site. This caused the bridge to begin vibrating and swaying as if it were a piece of paper in the presence of the wind, which destroyed its structure.

Another example of mechanical resonance is what we can always observe in films or drawings: the breaking of a glass with the high-pitched singing of a lyric singer. The cup is broken by having its natural frequency equal to the frequency of the sound waves emitted by the singer. In this way, it enters into resonance and begins to vibrate until it breaks.