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Nidzz93
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Wats the difference between progressive wave and stationary waves ?
HallsofIvy said:If you do that again and again at exactly the right frequency (the "natural" frequency which depends upon the density of the whip material and tension) the waves reflecting off the wall will add to and subtract from the incoming waves so that you have nodes (0 motion) at some points, highest and lowest points half way between them. That is the nodes and hightest and lowest are "stationary".
olivermsun said:When you pluck a stringed instrument, you are making a "kink" in the string which contains the fundamental and its overtones (not a continuum!). The highest overtones dissipate much more quickly, and so the tone quickly settles to something more like the fundamental and a few overtones (which gives the instrument its characteristic "sound").
Why do the higher overtones dissipate much quickly? Is it because of air resistance?
RedX said:Why do the higher overtones dissipate much quickly? Is it because of air resistance?
ZealScience said:To this question, I think it is because of higher frequency has higher energy carried with it. Higher energy like kinetic energy, means it interacts more vigorously with, for instance, air molecules, then energy dissipate faster.
seonshrestha said:does crest and trough cancel each other in stationary waves?and why are these waves called stationary waves ?
seonshrestha said:does this apply to electromagnetic waves too?
beantwin said:I've always sensed that our description of light as a wave is misleading. I can imagine it ACTUALLY being a progressive wave moving up and down because wouldn't that contradict the very idea of special relativity? Some light would would travel faster than others because not only is there the forward motion at light speed, but also the up and down (or side to side if you prefer) of the wave. Higher frequencies would travel faster to achieve the same speed as slower waves that need not oscillate as frequently.
So the question I ask is are we just calling it a traditional wave because it is simply convenient to do so or because light is, in fact, a wave jumbling back and forth while traveling at the ultimate speed limit across the universe?
Feedback would be helpful. I haven't had the chance to study this more as of yet, so I may, and probably am, overlooking a critical element that would resolve this dilemma.
sophiecentaur said:You get standing waves in signal lines and in some designs of RF filters. They are a real embarrassment in the lines between transmitters and antennae where then can introduce excessively high volts (High Voltage Standing Wave Ratio / VSWR).
sophiecentaur said:A wire dipole, fed at the centre, will present a load of 73ohms at just one frequency. (At which the dipole is an exact half wave long. All the energy is radiated into free space so this 'looks like' a pure resistance. Any practical antenna needs to radiate a range of frequencies (bandwidth) so it cannot be perfectly 'matched' to free space. A very short dipole will appear as a small Capacitance in series with a tiny resistance; that is almost an open circuit. A very long dipole can look like anything from a near open circuit to a near short circuit.
An antenna feeder will always have standing waves in it but these may be reduced by 'matching networks' at the antenna feed point.
sophiecentaur said:I guess it would have to be - as there isn't a negative gravitational field.
I'm aware of that. I was responding your earlier statement:sophiecentaur said:Surface waves are a combination of both longitudinal and transverse.
sophiecentaur said:if you wave your arm from side to side in a fluid, the fluid in front will not be moved. If you push your hand forward, the fluid in front can be made to move. A side to side motion will not propagate because there is no way a force can be transmitted. It's only through a difference in pressure (i.e. a longitudinal displacement) that a wave can be made to propagate.