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Brody, The dog, is sitting at your feet like a good boy. You throw a dog toy away from you at a speed of 34 m/s (assume constant horizontal
Question
Brody, The dog, is sitting at your feet like a good boy. You throw a dog toy away from you at a speed of 34 m/s (assume constant horizontal velocity). Brody runs after the ball at a constant speed of 7 m/s. The toy is designed to make a constant high frequency tone of 950 Hz as it flies through the air.What frequency do you hear the toy make?
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Physics
5 years
2021-08-13T21:42:28+00:00
2021-08-13T21:42:28+00:00 1 Answers
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Answer: 1054.53 Hz
Explanation: this is a question under the principle of Doppler effect .
Doppler effect is a mathematical statement that gives the value of the observed frequency by an observer when there is a relative motion between the observer and the source of sound.
This is mathematically given as
fo = (v + vo)/(v – vs) × f
Where fo = observed frequency =?
v = speed of sound in air = 343 m/s
vo = velocity of observer = 0 ( since I am at rest )
vs = velocity of the source of sound ( in this case the dog toy ) = 34m/s….this value is positive because it is moving away from the observer.
f = frequency of sound produced by source = 950 Hz
By substituting the parameters, we have that
fo = (343+0)/(343-34) × 950
fo = (343/ 309) × 950
fo = 1.11 × 950 = 1054.53 Hz