Question

Why do velocities add up if sound pressures cancel each other and vice versa. Im talking in terms of wave pulses travelling in opposite directions.

Answer 1

Answer:

With classical velocity addition, velocities add like regular numbers in one-dimensional motion: u = v + u′, where v is the velocity between two observers, u is the velocity of an object relative to one observer, and u′ is the velocity relative to the other observer.