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3 years ago

6

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?

1 answer:

Natali [406]3 years ago

5 0

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

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Where;

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With the new distance, 2·d, we get;

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Therefore;

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$C = \dfrac{Q}{V}$

Therefore;

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∴ V = 2 × V₀

The new potential difference, V = 2·V₀

Therefore, after the plates are 2·d apart, the new capacitance and potential difference between the plates are;

1/2·C₀, 2·V₀.

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3 years ago