I’m trying to understand the concept of relative velocity in the context of sound waves. When sound travels from a source to a receiver, I’m confused about how to calculate the wave’s velocity relative to the source (vwm). The equation Vfm = 80 m/s represents the velocity of the medium moving at a constant relative to the medium. Now, if I want to find the velocity of the medium moving from the source, why do I have to add up the velocity of the wave relative to the source and the velocity of the source relative to the medium? Also, when should I use the velocity of the medium relative to the source, and when should I use the velocity of the source relative to the medium?”
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I’m not quite sure what you are trying to say here but the formulas for using the doppler effects are quite simple.
If you wish to calculate the observed frequency; f_obs = (1+v_object/v_sound)*f_0
With f_0 being the original frequency. V_object is the difference in velocity between the source and the observer, with moving closer to each other being positive, and moving away being negative. v_sound is the speed of sound, or you can even change it to speed of light if you want to see doppler effects for light.
For calculating the speed of an object based on the frequency you measure(assuming you know the original frequency);
f_obs-f_0 = (v_object/v_sound)*f_0
I think the key take away is that you use the difference in velocity, not absolutes. Motion is relative. But if you know the motion of one object, you can calculate the motion of the other if you have all this information.
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