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## At an air show a jet flies directly toward the stands at a speed of 1230 km/h, emitting a frequency of 3140 Hz, on a day when the speed of s

Question

At an air show a jet flies directly toward the stands at a speed of 1230 km/h, emitting a frequency of 3140 Hz, on a day when the speed of sound is 342 m/s.

a. What frequency (in Hz) is received by the observers?

b. What frequency do they receive as the plane flies directly away from them?

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Physics
6 months
2021-07-29T23:46:16+00:00
2021-07-29T23:46:16+00:00 2 Answers
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## Answers ( )

Explanation:Given that,

Speed of the jet,

Frequency of the sound produced by jet, f = 3140 Hz

Speed of sound in air, v = 342 m/s

(a) The formula of the observed frequency is given in terms of Doppler’s effect as :

is the speed of observer

(b) Let f’ is the frequency received as the plane flies directly away from them. So,

Hence, this is the required solution.Answer:a.

b. which won’t be audible to the humans as the audible capacity of the human ear is from 20 Hz to 20,000 Hz.

Explanation:Given:

a.Since the sound source is moving therefore we can determine the observed frequency by the

Doppler’s effectgiven as:where:

observed frequency when the jet plane approaches the observers

observer’s velocity = 0

b.When the plane flies away from the observers then we take its velocity as negative.

where:

observed frequency when the jet plane flies away from the observers

observer’s velocity = 0

which won’t be audible to the humans as the audible capacity of the human ear is from 20 Hz to 20,000 Hz.