# physics help

posted by .

Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound waves in phase at 688 Hz. Take the speed of sound in air to be 344 m/s. If you are 3.00m from speaker A directly to your right and 3.50m from speaker B directly to your left, will the sound that you hear be louder than the sound you would hear if only one speaker were in use? What is the shortest distance d you need to walk forward to be at a point where you cannot hear the speakers? I know the answer to the first part is yes but I'm not sure how to find the answer for the second part. Please help!

• physics help -

wavelength = T*c = c/f = 344/688 = 2 meters

We want the distance to differ by half a wavelength, 1 meter

sqrt(3.5^2 +x^2) - sqrt(3^2+x^2) = 1

• physics help -

3.5^2 + x^2 = 1 + 2sqrt(9+x^2) + 9 + x^2

12.25 = 10 + 2 sqrt(9+x^2)

sqrt (9+x^2) = 2.25/2

square both sides and get x

• physics help -

Whoops, wavelength = 1/2 not 2
so they differ by .25 meter
the method does not change

## Similar Questions

1. ### physics

Two loudspeakers emit sound waves along the x-axis. The sound has maximum intensity when the speakers are 14.0 cm apart. The sound intensity decreases as the distance between the speakers is increased, reaching zero at a separation …
2. ### physics

Two loudspeakers emit sound waves along the x-axis. The sound has maximum intensity when the speakers are 14.0 cm apart. The sound intensity decreases as the distance between the speakers is increased, reaching zero at a separation …
3. ### physics

Two loudspeakers emit sound waves along the x-axis. The sound has maximum intensity when the speakers are 14.0 cm apart. The sound intensity decreases as the distance between the speakers is increased, reaching zero at a separation …
4. ### physics

Two loudspeakers in a 20°C room emit 629 Hz sound waves along the x-axis. (a) If the speakers are in phase, what is the smallest distance between the speakers for which the interference of the sound waves is destructive?
5. ### Two Loudspeakers in a open field Pjysics

Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound waves in phase at 688 Hz. Take the speed of sound in air to be 344 m/s. If you are 3.00m from speaker A …
6. ### physics

Two loudspeakers, A and B, are driven by the same amplifier and emit sinusoidal waves in phase. The frequency of the waves emitted by each speaker is 172 \rm Hz. You are 8.00 \rm m from speaker A. Take the speed of sound in air to …
7. ### physics

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint …
8. ### physics

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint …
9. ### physics

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint …
10. ### Physics

Imagine you are in an open field where two loudspeakers are set up and connected to the same amplifier so that they emit sound waves in phase at 688 Hz. Take the speed of sound in air to be 344 m/s. If you are 3.00 m from speaker A …

More Similar Questions