A stationary bagpiper is playing a Highland bagpipe, in which one reed produces a continuous sound of frequency 440 Hz. The air is still and the speed of sound is 340 m/s. A) What is the wavelength of the sound wave produced by the bagpipe?B)What is the frequency of the sound wave that a bicyclist hears if she is approaching the bagpiper at 10.0 m/s?C)What is the wavelength of the sound wave that a bicyclist hears if she is approaching the bagpiper at 10.0 m/s?D)What is the frequency of the sound wave that a bicyclist hears if she is moving away from the bagpiper at 10.0 m/s?E)What is the wavelength of the sound wave that a bicyclist hears if she is moving away from the bagpiper at 10.0 m/s?

Respuesta :

Answer:

(A) 0.773 m

(B) f' = 452.94 Hz

(C) [tex]\lambda' = 0.751\ m[/tex]

(D) f" = 427.058 Hz

(E) [tex]\lambda' = 0.796\ m[/tex]

Solution:

As per the question:

Frequency of the sound produced, f = 440 Hz

Speed of the sound in still air, v = 340 m/s

Now,

(A) To calculate the wavelength of the sound wave:

We use the relation:

[tex]v = f\lambda [/tex]

[tex]\lambda = \frac{340}{440} = 0.773\ m[/tex]

(B) By using Doppler effect to calculate the frequency of the sound wave:

Velocity of the receiver, [tex]v_{R} = 10.0\ m/s[/tex]

Velocity of the source, [tex]v_{S} = 0\ m/s[/tex]

When the receiver is approaching:

[tex]f' = \frac{v + v_{R}}{v}f = \frac{340 + 10}{340}\times 440[/tex]

f' = 452.94 Hz

(C) To calculate the wavelength of the sound wave:

[tex]\lambda' = \frac{v}{f'} = \frac{340}{452.94} = 0.751\ m[/tex]

(D) While moving away, the frequency of the sound wave can be calculated as:

[tex]f" = \frac{v - v_{R}}{v}f = \frac{340 - 10}{340}\times 440[/tex]

f" = 427.058 Hz

(E) The wavelength can be given by:

[tex]\lambda" = \frac{v}{f"} = \frac{340}{427.058} = 0.796\ m[/tex]