Speed of Theoretical Wave: Constant Regardless of Frame?

Click For Summary

Discussion Overview

The discussion centers around the speed of theoretical waves that do not require a medium, exploring whether their speed remains constant regardless of the observer's frame of reference. Participants examine the implications of the Doppler effect and the definitions of wave properties such as frequency and wavelength.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant states that the speed of a theoretical wave is given by the equation v=fl, where f is frequency and l is wavelength, suggesting that the speed remains constant despite changes in the observer's motion.
  • Another participant argues that the speed of such a wave is frame-dependent, particularly for waves characterized by energy and momentum, except for massless particles.
  • A participant questions the definition of the theoretical wave, emphasizing that frequency and wavelength are influenced by the source and medium, seeking clarification on the nature of such waves.
  • There is a suggestion that gravitational waves or sound waves in a super-fluid could serve as examples of such theoretical waves, though uncertainty remains about the definitions and characteristics of these waves.
  • Participants express confusion about the implications of medium on wave properties, with one noting that not everyone has a physics degree, highlighting the complexity of the discussion.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the constancy of wave speed across different frames of reference, with multiple competing views on the definitions and characteristics of theoretical waves. The discussion remains unresolved.

Contextual Notes

Limitations include unclear definitions of the theoretical wave, dependence on the interpretation of wave properties, and unresolved questions about the role of medium in defining wavelength and frequency.

ArielGenesis
Messages
238
Reaction score
0
In a theoretical wave that does not need a medium, not necessarily EM.
the speed of the wave is given by : v=fl
where f is frequency and l is lamda, wave length

suppose there is a stationary wave generator, we can easily measure f and l from any arbitrary point.
if we move towards the generator we will experience a Doppler effect, let's say, we move in such a way that we hear the frequency 2f. by doing this, the wavelength we detect become 0.5l and thus the speed is still v. so shouldn't any wave have a constant speed disregarding the frame of reference?
 
Physics news on Phys.org
The speed of such a wave is v=E/p, which is frame-dependent except for particles (quanta) of rest mass 0.
 
theoretical wave but what?

ArielGenesis said:
In a theoretical wave that does not need a medium, not necessarily EM.
the speed of the wave is given by : v=fl
where f is frequency and l is lamda, wave length

suppose there is a stationary wave generator, we can easily measure f and l from any arbitrary point.
if we move towards the generator we will experience a Doppler effect, let's say, we move in such a way that we hear the frequency 2f. by doing this, the wavelength we detect become 0.5l and thus the speed is still v. so shouldn't any wave have a constant speed disregarding the frame of reference?

Could you define such a wave? The frequency is defined by the source and the wave length by the source and the medium as well!
 
so the wavelength is defined by the medium, that's new!

sorry Ich, but I have no idea what you are about. pardon me but not every one here, especially me, got a degree in physics.

hummm could I define such a wave? I might...
1. I am not sure, a gravitational force wave, where there will be a stationary source object which m=sin(t) where m is mass and t is time/.
2. I am sure! a normal sound wave in a super-fluid, so there will be no viscosity...

is EM is the only wave without medium?
 

Similar threads

  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
3
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 23 ·
Replies
23
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 51 ·
2
Replies
51
Views
5K
  • · Replies 13 ·
Replies
13
Views
3K