Moving source - stationary observer
Stationary source - moving observer
For any wave the wavelength, frequency and velocity are related as shown: v = λf
This means that the change in frequency observed due to a moving observer or source must also result in a change in the wavelength or the velocity.
For a moving source, there is a continual change in the origin of the wave.
For a stationery source the origin of the wave does not change.
This means that the change in frequency observed due to a moving observer or source must also result in a change in the wavelength or the velocity.
For a moving source, there is a continual change in the origin of the wave.
At the observer,
the velocity of the wave is the same as at the source.
There is no correction for the velocity of the observer because the observer is stationary.
BUT the frequency is different than at the source due to the motion of the source.
This means that the wavelength is different than at the source.
The frequency and wavelength change in opposite directions in accord with the relationship above.
the velocity of the wave is the same as at the source.
There is no correction for the velocity of the observer because the observer is stationary.
BUT the frequency is different than at the source due to the motion of the source.
This means that the wavelength is different than at the source.
The frequency and wavelength change in opposite directions in accord with the relationship above.
For a stationery source the origin of the wave does not change.
At the observer
the wavelength of the wave is the same as at the source
The change due to the motion of the source is not observed.
the frequency is different than at the source due to the motion of the observer.
the velocity is different than at the source due to the motion of the observer.
The direction of change of the velocity depends on the relative motion of the wave and the observer.
The wave moves from the source toward the observer. If the observer moves
the wavelength of the wave is the same as at the source
The change due to the motion of the source is not observed.
the frequency is different than at the source due to the motion of the observer.
the velocity is different than at the source due to the motion of the observer.
The direction of change of the velocity depends on the relative motion of the wave and the observer.
The wave moves from the source toward the observer. If the observer moves
in the opposite direction (toward the source),
the wave velocity at the observer is higher than at the source (v = vw + vobs).
in the same direction (away from the source),
the wave velocity at the observer is lower than at the source (v = vw – vobs).
the wave velocity at the observer is higher than at the source (v = vw + vobs).
in the same direction (away from the source),
the wave velocity at the observer is lower than at the source (v = vw – vobs).