# Sound waves travelling different paths

## The Attempt at a Solution

So at the sound source, the waves are split in half I guess, and each of those halves travel into the different directions. Path SAD is constant and SBD is not, so the waves are changing in path SBD. Since the sound waves are changing, do I need to use derivatives somewhere?

CWatters
Homework Helper
Gold Member
No. The sound waves aren't "changing" (at least not in frequency) they just travel a longer path in SBD. Under what conditions do you get constructive and destructive interference at D? What equation relates velocity, frequency and wavelength?

No. The sound waves aren't "changing" (at least not in frequency) they just travel a longer path in SBD. Under what conditions do you get constructive and destructive interference at D? What equation relates velocity, frequency and wavelength?

When a crest of a wave meets a crest, it's constructive and when a crest meets a trought it's destructive. The wavespeed = wavelength * frequency is the equation you describe, I think.

However, I do not understand the physics that is going on. Why are you considering constructive and destructive interference? Why is the equation that relates velocity, frequency and wavelength important here? I don't physically see the relationships between the line of thinking and the problem.

CWatters