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- Speed of Sound in a fluid
|
(153) |
where is the bulk modulus of the fluid and is the density.
These quantities vary with pressure and temperature.
- Speed of Sound in air is
m/sec.
- Doppler Shift: Moving Source
|
(154) |
where is the unshifted frequency of the sound wave for receding
(+) and approaching (-) source.
- Doppler Shift: Moving Receiver
|
(155) |
where is the unshifted frequency of the sound wave for receding
(-) and approaching (+) receiver.
- Stationary Harmonic Waves
|
(156) |
for displacement waves in a pipe of length closed at one or both
ends. This solution has a node at (the closed end). The
permitted resonant frequencies are determined by:
|
(157) |
for (both ends closed, nodes at both ends) or:
|
(158) |
for (one end closed, nodes at the closed end).
- Beats
If two sound waves of equal amplitude and slightly different frequency
are added:
which describes a wave with the average frequency and twice the
amplitude modulated so that it ``beats'' (goes to zero) at the
difference of the frequencies
.
Next: Sound Waves in a
Up: Sound
Previous: Sound
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Robert G. Brown
2004-04-12