How to Determine the Sign of the Doppler Shift?

Thread starter nao113
Start date Jun 8, 2022
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Doppler System

In summary, the Doppler Effect is a phenomenon that occurs when there is a change in frequency of a wave due to the relative motion between the source of the wave and the observer. It works by changing the wavelength of the wave, resulting in a higher or lower frequency and pitch depending on the direction of motion. The equation for the Doppler Effect is Δf/f = v/c and it is used in everyday technologies such as radar, sonar, and medical ultrasound. However, it has limitations such as requiring relative motion and assuming constant wave speed. It also cannot be applied to stationary objects or objects moving at a constant speed.

Jun 8, 2022

nao113

Homework Statement: If the velocity of the target is positive, ∆𝑓 > 0.
If the velocity of the target is negative, ∆𝑓 < 0. How to identify the sign of ∆𝑓 in Doppler system?

Did I answer it correctly? thank you

Relevant Equations: I put that in the picture below

answer:

Last edited: Jun 8, 2022

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Jun 9, 2022

haruspex

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I don't know what answer is wanted. As I read it, both the problem statement and your answer assert that the sign of the shift tells you whether the relative velocity is positive or negative. But the question is asking how you determine the sign of the shift, no?

1. What is the Doppler Effect?

The Doppler Effect is the perceived change in frequency of a wave when the source of the wave is moving relative to the observer. This can be observed in sound waves, light waves, and other types of waves.

2. How does the Doppler Effect work?

The Doppler Effect works by altering the wavelength of a wave as the source of the wave moves closer or farther away from the observer. This causes a change in the frequency of the wave, resulting in a perceived change in pitch or color.

3. What is the formula for calculating the Doppler Effect?

The formula for calculating the Doppler Effect is: Δf = f₀(v ± vo) / (v ± vs), where Δf is the change in frequency, f₀ is the original frequency, v is the speed of the wave, vo is the speed of the observer, and vs is the speed of the source.

4. How is the Doppler Effect used in real life?

The Doppler Effect is used in various real-life applications, such as in weather forecasting to track the movement of storms, in medical imaging to measure blood flow, and in astronomy to determine the speed and direction of stars and galaxies.

5. What is the difference between the Doppler Effect and the Doppler Shift?

The Doppler Effect and the Doppler Shift are often used interchangeably, but the Doppler Shift specifically refers to the change in frequency of a wave due to relative motion between the source and observer. The Doppler Effect is a broader term that encompasses all types of waves, not just sound and light waves.