# Tag Info

### Can sound waves be reflected/absorbed using a microwave-oven type mesh?

Acoustic waves are mechanical, not electromagnetic. Acoustic waves propagate as standing waves of pressure through a transfer medium. Both wave types can travel radially in 3 dimensions. The acoustic ...

### Why is the ground mode the only excited mode in acoustics?

It is not surprising that researchers would have neglected to analyze the contributions of higher order harmonics. Generally, in most physical systems higher order modes contribute progressively less ...
Accepted

### Is there a publication on the speed of sound assuming heat conduction is taken into account?

Mechanical Radiation by Robert Lindsay discusses the effects of heat flow on sound waves in Section 9.12. The discussion is primarily couched in terms of attenuation, but as a side result of this ...

### Can human ear hear 4 Hz frequency, if I tap my hand 4 times per second on table?

This video of Euler's disk provides a useful example. Listen to the sounds. Around 0:30, you can hear a noise in 4Hz or so. You will notice that it's clearly "pulsing" - you can tell the ...

### How is energy distributed over the normal modes?

(1): if you solve the linear eigenvalue system of normal modes, you can construct the most general solution as $f \propto \sum_j c_j o_j(t) d_j(x)$ where $o_j(t)$ is the time dependence of mode $j$ ...
1 vote

### The physics behind the circle / spiral of fifths

There are physiological reasons why the octave (2:1 ratio) and the perfect fifth (3:2 ratio) sound particularly harmonious to the human ear. The perfect fourth (4:3 ratio) also sounds harmonious, and ...
Accepted

### Is sound really adiabatic because it is a fast process?

Sound propagation is indeed better modeled as an isothermal process at higher frequencies, for exactly the reason you note: With a shorter wavelength, the hotter and colder regions are closer and more ...

1 vote

### How do you interpret the statement that a wave is a travelling wave if $f(x,t) = f(x \pm vt)$?

In this context, to me this is shorthand for, the function $f(x,t)$ of position $x$ and time $t$ is a (linear) combination of a function of $x+vt$ and a function of $x-vt$.
1 vote

### How do you calculate phase from sin wave equation?

For the equation you have assumed, the phase shifts by time but stays the same. So you could simply ignore the $\omega t$ for the sake of simplicity. Therefore, to be sure of the phase, you could ...
Well, the equation you present is not the wave equation but one of the many possible solutions to it. The phase $\phi$ refers to the value of the solution at $t = 0$ for a distance from the source \$x =...