# Homework Help: Phase difference question

1. Sep 15, 2008

### jrrodri7

1. The problem statement, all variables and given/known data
Two Loud speakers are placed on a wall 3.79 meters apart. A listener stands directly in front of one of the speakers, 65.6 meters from the wall. The speakers are being driven by the same electric signal generated by a harmonic oscillator of frequency 4010 Hz The speed of sound in Air is 343 m/s. What is the phase difference $$\Delta\Phi$$ between the two waves? (answer in radians)

2. Relevant equations
y = A sin (kx (+/-) $$\omega$$t

3. The attempt at a solution
I tried finding the wavelength and using trig to find the distance between the observer and speakers...but I'm not sure if it has anything to do with the problem, and I haven't gotten an answer out of this yet...I'm lost. The only thing I know is superposition, but I know that if you just add sin to sin, you don't just get sin, and I don't know how to derive that to see how that works....

HELP!

2. Sep 15, 2008

### LowlyPion

Sure it does. The difference in distance is going to determine what lag there is between the 4010 hz sound waves.