DEFINITIONS VIBRATIONS, WAVES AND SOUND

VIBRATIONS, WAVES AND SOUND

1. Vibration

a. understanding vibration

Vibration is: back and forth motion of objects on a regular basis through the balance point. One of the characteristics of vibration is the amplitude (the largest intersection of a vibration).

b. Period and frequency of vibration

Each of the vibrating body always has a vibrating frequency and period. Is the purpose of the frequency of vibration? And what is the purpose of the period of vibration? How is the relationship between frequency and period of vibration?

The period is the time that is required to do one thing vibrations. Periods expressed in units of second.

The period can be expressed as a mathematical formula as follows.

Vibration period (T) = time shakes / Total vibration (n)

Frequency is the number of vibrations in one second. Unit of frequency is the hertz (Hz) frequency can be expressed in terms of mathematics as follows:
Frequency (f) = Total vibration / vibration time (t)
         The relationship between the frequency and the period is stated as follows:
F = 1 / T
  T = 1 / f
          Description: f = frequency T = period

2. wave

a. understanding wave

Waves are vibrations that propagate. Waves occur because the vibration source. Waves propagate wave energy, while the middlemen do not come creeping.

b. Various wave

• according to the intermediary substance

1. Mechanical wave: the wave propagation requires a medium, eg, water waves and sound waves.

2. The electric wave: the wave that propagates not require medium. Examples of radio waves and light waves

• according to the direction of propagation and the direction of vibration

1. Transverse waves

is the wave of the direction perpendicular to the direction of vibration. Transverse wave-shaped hills and valleys wave waves propagate. Examples of waves on a string, surface water and light waves.

Images of transverse waves:

                                                                

Wavelengths in the transverse waves

Wavelength is the length of a wave consisting of the hills and valleys of the waves. Wavelength symbolized by lambda () and its unit is meter

2. Longitudinal wave

Longitudinal wave is a wave whose direction of vibration parallel to the direction of propagation. Longitudinal wave-shaped density. For example, the sound waves.

Images of longitudinal waves:

The length of the longitudinal wave

The length of the longitudinal wave is a wave length that consists of one density.

• wave period (T)

is the time that is required to take a single wave, its unit is second (s)

• The frequency of the wave ((f)

That is the number of waves that form in one second, the unit is Hz (hertz)

• Propagation of wave (v)

is the distance traveled in one second wave, its unit is meter / second (m / s)

• The relationship between the display waveform, period, frequency, and wave propagation speed.

• The basic formula is the wave: λ = vT or v = λ / T and f = 1 / T then v = λ f

v = wave propagation speed (m / s)

λ = wavelength (m)

T = period (s)

f = frequency (Hz)

According to the amplitude and phase:

1. The wave is a wave whose amplitude and phase equal at every point through which the waves.

2. The silent wave (stationary) is wave amplitude and phase change (not the same) at every point through which the waves.

• According to the intermediary medium:

1.. mechanical wave is the wave propagation in the medium requires intermediaries. Almost all the waves are mechanical waves.

2. Electromagnetic waves are waves in the propagation medium does not require intermediaries. Example: gamma ray (γ), X-rays, ultraviolet light, visible light, infrared, radar waves, TV waves, radio waves.

3. sound

a. understanding sound

sound is the product of the vibrating body. Objects that produce sound called sound sources. Vibrating sound source will vibrate the air molecules around it. Thus, the terms of the sound is the vibrating body. Require sound propagation medium. We can hear the sound if there is a medium to propagate sound

b. Terms of sound

1. There is a vibrating body (the sound source)

2. there is a medium that sends sound, and

3. No recipients are within the range of sound sources

The sound has a finite propagation speed. The sound takes to move from one place to another. Rapid propagation of sound was not too big. Rapid propagation of sound is much smaller than the propagation of light premises. Even now people have been able to make a plane that can fly several times faster than the propagation of sound. Rapid propagation of sound is often formulated as follows:

v = s / t

v = propagation speed of sound (m / s), s = distance of the source to the observer (m), t = time interval (s)

c. nature sounds
1. It is a longitudinal wave
2. Can not propagate in a vacuum
3. The speed of propagation is affected by propagation medium density (solid, liquid, gas). Fastest on medium high density.
4. Can resonance and reflection.
The sound can be experienced resonance. What's that resonance? Understanding the events took vibrating resonance is due to vibration of an object of another object, because the same frequency. The sound can undergo reflection, sound reflection process utilized at:
• Determination of the propagation of sound
• The detection of defects and cracks in the metal pipe
• The geophysical survey
• Measurement of the thickness of the metal plate
• Measuring the depth of the place.

d. kind of noise
1. infrasonic sound: the sound frequency less than 20 Hz, and can be heard by dogs, crickets, geese and horses.
2. The audiosonic sound, namely sound whose frequency is as between 20 Hz and 20,000 Hz can be heard by humans.
3. The ultrasonic sound, the sound frequency over 20,000 Hz, can be heard by bats and dolphins.
4. Tones, which sound whose frequency is irregular.
5. Wheezing, namely sound whose frequency is irregular.
6. Echoes or boom, which in part reflected sound that comes together with the original sound, thus disturbing the original sound.
7. Gema is, reflected sound that comes after the original sound, thus reinforcing the original sound.