If sound is a propagated by particles hitting each other in a tranverse wave, why doesn't pitch affect the speed of sound? Since frequency is the speed at which the particles hit in a period of time, and if the distance between particles are the same, thefore the speed of the particle should be faster, thus the speed of sound. Why is this wrong? What about volume? Since the intensity of the particles hitting each other and consequently the eardrum determines the volume, and since force is mass times acceleration, and the mass of the particle is constant, shouldn't the speed differ?
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3Sound is transmitted by longitudinal waves rather than transverse. "frequency is speed..." makes no sense. – M. Enns May 15 '16 at 15:01
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Not sure what you mean by "volume"? – jim May 15 '16 at 20:48
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For small enough amplitudes, the speed of sound is independent of how loud the sound is. It is also true that for a wide range of frequencies, the speed of sound doesn't vary with the pitch. When you move to large amplitudes (the assumptions of linear material are challenged) and high frequencies (when the wavelength of the sound is comparable to the spacing between the particles) you will find that the speed of sound varies. When the speed of the wave through a medium depends on its frequency the medium is called dispersive. Not sure if there is any particular name when the sound depends on how loud the noise is.
jim
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The energy of the wave is dependent on the amplitude of the wave. The amplitude is a measure of loudness of sound. Suppose we have a medium and all the particles in it are in equilibrium. Now we give a disturbance to a particle (or group of particles), which appears as a wave. The wave's velocity is dependent on the properties of the medium (this reasoning is logical since the wave itself is produced by the motion of the particles characterizing the medium). So the velocity is a constant for an isotropic medium.
Now, if you increase the energy of the wave, the amplitude (which is the maximum displacement of the particle from the equilibrium position) also increases. The increase in energy of the wave appears as the kinetic energy of the particles. So the velocity of the particles in the vibratory motion also increases which enables it to travel more distance from the equilibrium position in a given interval of time. This is how the amplitude of the wave increases. If you increase the speed, the wave travels more distance in a given time (or say, per second), which means the frequency of the wave is unaffected.
The wavelength is the distance between two consequent particles that are in the same phase of vibration. To reach to that particular particle, we must start from a particle and travel a distance with a velocity equal to that of the wave in a time equal to the period of the wave. Period has no change. So the wavelength also suffers no change.
This means the velocity of the wave suffers no change if you increase the amplitude.
UKH
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The speed of sound is determined by the "springiness" of air. Speed of sound in metals which have a much higher mechanical coefficient of expansion (compressive modulus, bulk modulus) is correspondingly higher. The longitudinal propagation of the sound energy does have an energy(intensity), but the value of that energy doesn't really affect the "spring constant". The frequency and wavelength are inversely related, but unlike the case in quantum mechanics, the energy is not determined by the frequency.
You can get more specifics in this Khan Academy video
DWin
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