Doppler shift source velocity components

In summary, the doppler effect occurs when there is relative motion between a source and an observer, causing a change in the observed frequency. However, when the source is moving perpendicular to the line between it and the observer, there is no change in frequency because the radial velocity of the source relative to the observer is zero. This means that although the distance between the source and observer may be changing, there is no relative motion along the line of sight. This type of motion is similar to a rotating motion, where one object is stationary and the other is always moving but does not get any closer or farther from the fixed point. When the observer and source are not moving in a straight line, the velocity of the observer and source should be taken
  • #1
undividable
24
0

Homework Statement


Why does a source moving perpendicular to the line between it and the observer produce no doppler effect?

Homework Equations


source-and-observer-towards-each-other.png


The Attempt at a Solution


I have heard the the radial velocity of the source relative to the observer must be zero but i don't understand why, if the distance between the source and the observer is increasing or decreasing , shouldn't there be a doppler effect since the wave length is changing?
 
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  • #2
undividable said:

Homework Statement


Why does a source moving perpendicular to the line between it and the observer produce no doppler effect?

Have you tried to figure out what sort of motion that represents?
 
  • #3
Try to think of a type of motion, where one object is stationary, and the other object is always moving, yet does not get any closer or farther from the fixed point.
 
  • #4
i guess my real question is, how does the doppler effect work when the observer and source are not moving in a straight line, what do we take in as the velocity of the observer and the source in the doppler effect equation?
 

1. What is Doppler shift?

Doppler shift is a phenomenon in which the frequency or wavelength of a wave appears to change when the source of the wave is moving relative to the observer.

2. How does Doppler shift relate to source velocity components?

Doppler shift is directly related to the velocity components of the source, as the speed and direction of the source's movement will affect the observed frequency or wavelength of the wave.

3. What are the two components of source velocity that affect Doppler shift?

The two components of source velocity that affect Doppler shift are the radial velocity, which is the component of motion towards or away from the observer, and the tangential velocity, which is the component of motion perpendicular to the observer's line of sight.

4. How does the direction of source velocity affect Doppler shift?

The direction of source velocity, specifically the angle at which the source is moving relative to the observer's line of sight, determines the amount of Doppler shift. A source moving towards the observer will have a higher frequency or shorter wavelength, while a source moving away will have a lower frequency or longer wavelength.

5. What are some real-world applications of Doppler shift and source velocity components?

Doppler shift and source velocity components are used in various fields, such as astronomy, meteorology, and traffic monitoring. In astronomy, it is used to determine the speed and direction of celestial objects. In meteorology, it is used to track the movement of storms. In traffic monitoring, it is used in radar guns to measure the speed of moving vehicles.

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