Would the Doppler Effect still apply in an observers reference frame if the observer would be the one moving past the ambulance instead of the ambulance moving (relative to the air)?
In: Physics
Yes, every movement is relative, the movement relative to the ground is not relevant for the effect, just the relative movement between the two.
The Doppler effect applies to any wave, including light.
Light doesn’t have a universal reference frame (no equivalent of the air).
Yes, providing the speeds involved are much less than the speed of sound through air, everything should be nice and symmetrical.
Yes. The frequency shift is different if the listener is moving and the source is stationary compared to the listener is stationary and the source is moving. Also different if moving away or towards each other. Basically 4 cases.
Both moving towards or away would be yet 2 more cases.
In the observer’s reference frame, the observer does not move. To the observer, the ambulance (and everything else in the world including the ground) is moving.
There’s videos out there that might help you visualize this.
The one I saw was a set of 6 second clips from 3 spots. It involved a car holding the horn for the 6 seconds in all 3. One view point was where the car passed at 3 seconds, one view point was inside the car, and one view point was a car passing the other direction.
Stationary view point: standard Doppler pitch shift.
Noisy car view point: no pitch shift.
Counter direction car: much stronger Doppler pitch shift.
If you can find a similar set of clips it might help, but if you want to just take my word at the descriptions that’s fine too. The point is, Doppler effects are all about relative movement. If the relative movement is 0, the Doppler pitch shift will be non-existant (2nd clip). If the relative movement is greater, the Doppler pitch shift will also be greater (3rd clip).
Latest Answers