In a longitudinal or transverse wave, what is the difference between the rest axis and the rest position? What do both represent?

1 Answer
Feb 26, 2017

I think these two terms are referring to essentially the same thing. Discussion below...

Explanation:

In the diagram below, the dashed line represents the rest position of the medium. This is where the medium would lie if undisturbed by the wave.

http://www.physicsclassroom.com/class/waves/Lesson-2/The-Anatomy-of-a-Wave

I must admit that I have not heard the term "rest axis" used in relation to this type of wave, but I assume it would refer to the same thing. Perhaps nothing more than a change of terminology? The rest axis is drawn to show the rest position of the medium?

In a longitudinal wave, a rest axis would apply only if we are considering a two-dimensional wave. There would be lines, perpendicular to the direction of travel of the wave, that would consist of particles that are undisturbed at a given moment. I don't see that the term would apply to a one-dimensional travelling longitudinal wave.