What is the definition of wave speed?

  • Thread starter Thread starter ShudyShab
  • Start date Start date
  • Tags Tags
    Speed Wave
AI Thread Summary
Wave speed can be defined as the rate at which energy is transferred by a wave, with specific distinctions for different types of waves. For a progressive wave, speed refers to the distance traveled by each peak in a given time, known as phase velocity, while for a wave packet, it is the speed of the envelope, termed group velocity. A standing wave, however, has a speed of zero since its peaks do not move, but it still possesses a frequency as points oscillate in place. The speed of a stationary wave can be described as the speed of either the incident or reflected waves that create it. This nuanced understanding is essential for accurately defining wave speed in various contexts.
ShudyShab
Messages
3
Reaction score
0
Hi :) I just want to know how you would simply define the speed of a wave in words?
Because I often get questions asking to define the speed of a standing wave etc.

One of the definitions I know for progressive wave is the rate at which energy is transferred by a wave.

but what about the speed of a standing wave?
 
Physics news on Phys.org
Speed can mean different things.

1. The speed of a simple sine wave is the distance that each peak of the sine curve shape travels in a given amount of time (phase velocity).

2. The speed of a wave packet is the distance that the peak of the wave packet's envelope curve travels in a given amount of time (group velocity). Energy travels at the group velocity.

3. In non-scientific usage, "speed" may also refer to the rate in time at which a fixed point in space waves on and off. In science, we call this the "frequency" of the wave, not the "speed".

So, a standing wave has a speed of zero, because the peaks do not travel, but has a non-zero frequency, because points are still waving on or off (or up or down for transverse waves). Take a look at my http://faculty.uml.edu/cbaird/95.658%282011%29/Lecture3.pdf" for a more rigorous explanation.
 
Last edited by a moderator:
Thank you :) I'll check out all the links
 
can't we define the speed of stationary wave as follows:-

Stationary wave is produced by the superposition of incident and reflected waves and the speed of stationary wave is the speed of anyone of the incident or reflected wav.

(As given in marking scheme of CIE).
 
Thanx that's perfect! Its exactly what I need as I am writing CIE
 

Thread 'Derivation of Hamilton's Principle: Questions'

I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
View full post »

Similar threads

Why Can a Sound Wave Not Travel Faster than the Average Molecule Speed?
Replies
23
Views
4K
What is the Relationship Between Interference and Wavelengths?
Replies
4
Views
1K
Exactly how do pressure waves work at the molecular level?
Replies
49
Views
4K
Addition of Harmonics in a string wave
Replies
4
Views
1K
B Acoustic levitation: high or low pressure?
Replies
4
Views
2K
Why is there a set speed of sound in a certain medium?
Replies
7
Views
2K
Is the Hull Speed Debate Misleading: Online vs. Textbook Perspectives?
Replies
5
Views
3K
What Does Speed Mean in the Context of Standing Waves?
Replies
1
Views
5K
I Speed of information in a medium
Replies
38
Views
4K
Are there exceptions to the rule of speed and energy for waves?
Replies
2
Views
4K

Hot Threads

Recent Insights

Back
Top