Question

Do sound waves transport linear momentum or act as a source term?

Answer 1

relation

w(k)∝|sin(ka2)|w(k)∝|sin⁡(ka2)|.

Now, looking at small kk, we can approximate that sin(ka/2)=ka/2sin⁡(ka/2)=ka/2 so that w(k)∝kaw(k)∝ka. The textbook states that this limit describes sound waves and this is exactly what I do not quite understand. Which formula is pointing out that we are dealing with sound waves? I have read Why can the dispersion relation for a linear chain of atoms (connected by springs) be written as ω(k)=cs|k|ω(k)=cs|k|? and the corresponding comments where it says:

Answer 2

Hola mate !! ✨✨

here's your answer...⬇️⬇️

▶️We know that sound wave or simply sound is a form of energy. since anything having energy has a momentum therefore sound wave has linear momentum and acts as a source for its transportation.

hope it helps !! ❤️❤️