Question

To understand the terms in the Doppler shift formula.

The Doppler shift formula gives the frequency fL

f

L

at which a listener L hears the sound emitted by a source S at frequency fS

f

S

:

fL=fSv+vLv+vS

f

L

=

f

S

v

+

v

L

v

+

v

S

,

where v

v

is the speed of sound in the medium, vL

v

L

is the velocity of the listener, and vS

v

S

is the velocity of source.

Part A Part complete

The velocity of the source is positive if the source is ______________. Note that this equation may not use the sign convention you are accustomed to. Think about the physical situation before answering.

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The velocity of the source is positive if the source is ______________. Note that this equation may not use the sign convention you are accustomed to. Think about the physical situation before answering.

traveling in the +x direction

traveling toward the listener

traveling away from the listener

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Correct

Part B Part complete

The velocity of the source is measured with respect to the ________.

The velocity of the source is measured with respect to the ________.

medium (such as air or water)

listener

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Correct

Part C

The velocity of the listener is positive if the listener is _____________.

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The velocity of the listener is positive if the listener is _____________.

traveling in the +x direction

traveling toward the source

traveling away from the source

Submit

Part D Complete previous part(s)

Part E

Imagine that the source is to the right of the listener, so that the positive reference direction (from the listener to the source) is in the +x

+

x

direction. If the listener is stationary, what value does fL

f

L

approach as the source's speed approaches the speed of sound moving to the right?

Imagine that the source is to the right of the listener, so that the positive reference direction (from the listener to the source) is in the direction. If the listener is stationary, what value does approach as the source's speed approaches the speed of sound moving to the right?

0

12fS

1

2

f

S

2fS

2

f

S

It approaches infinity.

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Part F

Now, imagine that the source is to the left of the listener, so that the positive reference direction is in the −x

−

x

direction. If the source is stationary, what value does fL

f

L

approach as the listener's speed (moving in the +x

+

x

direction) approaches the speed of sound?

Now, imagine that the source is to the left of the listener, so that the positive reference direction is in the direction. If the source is stationary, what value does approach as the listener's speed (moving in the direction) approaches the speed of sound?

0

12fS

1

2

f

S

2fS

2

f

S

It approaches infinity.

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Part G

In this last case, imagine that the listener is stationary and the source is moving toward the listener at the speed of sound. (Note that it is irrelevant whether the source is moving to the right or to the left.) What is fL

f

L

when the sound waves reach the listener?

In this last case, imagine that the listener is stationary and the source is moving toward the listener at the speed of sound. (Note that it is irrelevant whether the source is moving to the right or to the left.) What is when the sound waves reach the listener?

0

12fS

1

2

f

S

2fS

2

f

S

It approaches infinity.

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Answer 1