Understanding the Relationship between Variables in a Wave Equation

Click For Summary

Discussion Overview

The discussion revolves around understanding the relationship between the variables x and t in the wave equation y(x,t) = A sin(kx - ωt). Participants explore the nature of these variables, their independence, and how they relate to the wave's behavior over time and space.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant expresses confusion about the relationship between x and t, suggesting that if ν = x/t, then kx = ωt must hold for all points on the wave.
  • Another participant asserts that x and t are independent variables, explaining that the wave equation allows for examining the wave at a fixed time or a fixed position independently.
  • A participant describes generating a sinusoidal wave using a spreadsheet, questioning whether fixing one variable to zero implies the other must also be zero.
  • In response, another participant clarifies that the wave function is defined in terms of two free variables, allowing for analysis of the wave at constant time or position.
  • One participant shares their experience with a resource that helped them understand the concept of functions dependent on two variables, particularly in the context of wave equations.
  • Another participant notes the challenge of visualizing functions of two variables in 3D space, describing how such functions can be represented as surfaces.

Areas of Agreement / Disagreement

Participants exhibit differing views on the relationship between x and t, with some asserting their independence while others explore potential connections. The discussion remains unresolved regarding the implications of fixing one variable in relation to the other.

Contextual Notes

Some participants express difficulty in grasping the graphical representation of functions with two variables, indicating a potential limitation in understanding the wave equation's behavior.

bluestar
Messages
80
Reaction score
0
I am unable to determine the relationship between x and t in the following equation.

[tex] y\left(x,t\right)=A\sin\left( kx-\omega t \right)\\[/tex]


If [tex]\nu=\frac{x}{{t}}[/tex] then the numbers within the bracket goes to zero; because [tex]kx=\omega t[/tex]
for all points on y(x,t).

Can anyone enlighten me please?
 
Physics news on Phys.org
x and t are independent variables; there is no relationship between them. That equation describes a wave. Pick any time t_0, then you can look at the whole wave in space (along x). Pick a point x_0, and you can see how that point oscillates in time. Both can be looked at independently.
 
I set-up a spreadsheet and generated a sinusoidal wave starting at x0 which progresses parallel along the positive x-axis.
If I leave t=0, then any value I plugged in for x falls on the curve.
Likewise, if I left x=0, then any value I plugged in for t falls on the curve.

Does this mean when one variable has a value then the other must be 0?
 
No. It's a wave function of two free variables, x and t--longitudinal position and time. Pick any constant t and you have a standing wave at t. Let t be a variable to see the evolution of the wave over time.
 
Last edited:
I had trouble grasping the concept of how to graph a function depended on two variables. I found a site that presented a simple Gaussian wave and then progressed to a Gaussian Wave dependent on two variables. The page wraps up with a general equation of a cosine function dependent on two variable including axes offsets.

I found it to be a great site for explaining the implication of a function with two independent variable. Now I understand a little better what is happening in the wave equation.


http://resonanceswavesandfields.blogspot.com/2007/08/true-waves.html
 
bluestar said:
I had trouble grasping the concept of how to graph a function depended on two variables.

In 3D space a function of two variables can be drawn as a surface, wavy in both directions in your case.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K