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Speakers A and B are vibrating in phase. They are directly facing each other, are 7.80 m apart, and are each playing a 73.0 - Hz tone. The speed of sound is 343 m/s. One the line between the speakers there are three points where constructive interference occurs. What are the distances of these three points from speaker A?

Respuesta :

Answer:

x =    6.25 m  , x = 3.90 m  , x =   1.55 m

Explanation:

given,

frequency of tone = 73 Hz

speed of sound = 343 m/s

distance between the speaker = 7.80 m

wavelength (λ) = [tex]\dfrac{v}{\mu}[/tex]

                    = [tex]\dfrac{343}{73}[/tex]

                    = 4.7 m

let the distance from speaker A be  x      

distance from speaker B be 7.80 - x

distance of the first point from speaker A

x - (7.80 - x) = one wavelength

 2x - 7.80 = 4.7

x =    6.25 m

distance of the second point from speaker A

  x - (7.80 - x) = zero wavelength

 2x - 7.80 = 0

x = 3.90 m

distance of the second point from speaker A

(7.80 -x) - x = one wavelength

7.80 - 2x = 4.7

x =   1.55 m

Answer:

The distances of these three points from speaker A are 6.25 m, 3.9 m and 1.55 m.

Explanation:

Given that,

Distance = 7.80 m

Frequency f = 73.0 Hz

Speed of sound = 343 m/s

We need to calculate the wavelength

Using formula of wavelength

[tex]\lambda=\dfrac{v}{f}[/tex]

Put the value into the formula

[tex]\lambda=\dfrac{343}{73.0}[/tex]

[tex]\lambda=4.6986\ m[/tex]

Let the distance from speaker A is x.

The distance from speaker B is (7.80-x).

Difference between the distance must be a whole number of wavelength.

For first point,

[tex]x-(7.80-x)= \lambda[/tex]

Put the value of wavelength

[tex]2x-7.80=4.6986[/tex]

[tex]2x=4.6986+7.80[/tex]

[tex]x=\dfrac{12.4986}{2}[/tex]

[tex]x=6.25\ m[/tex]

For second point,

[tex]x-(7.80-x)= \lambda[/tex]

Put the value of wavelength

[tex]2x-7.80=0[/tex]

[tex]x=3.9\ m[/tex]

For third point,

[tex](7.80-x)-x= \lambda[/tex]

Put the value of wavelength

[tex]7.80-2x=4.6986[/tex]

[tex]-2x=4.6986-7.80[/tex]

[tex]2x=3.1014[/tex]

[tex]x=\dfrac{3.1014}{2}[/tex]

[tex]x=1.55\ m[/tex]

Hence, The distances of these three points from speaker A are 6.25 m, 3.9 m and 1.55 m.

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