Period, frequency and velocity amplitude


There are many types of mechanical waves, such as sound waves, water waves, seismic waves ... In addition to wavelength, there are some other important quantities of waves which we will study the following.

Experiment

Take a thin elastic metal rods, mounted at the top of a small marble (or a needle). Place the metal rod so that marbles touch point P on the surface of a fairly large water tray. If elastic metal bar, just strummed lightly on top of the bar also makes marbles oscillation cycle period T, and the element of water in contact with it also regulate the oscillation cycle T in quite some time long. The oscillation of marbles on the water creating circular waves centered at P. This wave spread out every way.

Conclusion

At every point where the mechanical waves passing through, the physical element to oscillate with the same cycle, with cycles of oscillation T wave source. General Period of physical elements transmitted wave is called the wave oscillation periods and the inverse of f = 1 / T is called oscillation frequency of the wave.

In the example above survey, we see that after a period of oscillation, the oscillation phase transmission distances, the distance is called wavelength λ (see screenshot below).

Wavelength is the distance the wave travels during an oscillation cycle of the wave.
Phase velocity oscillations called velocity v. Because the T-wave cycle is a distance transmissions by wavelength λ, we have the formula:
λ = vT or λ = v / f


3DEd™ v2.0 - Simulation software, mechanical wave