00:01
Bopper effect accounts for the shift or the change in the frequency on relation to movement.
00:07
And it is solved as the following.
00:09
Where fl is the frequency heard by the listener, fs is the actual frequency emitted by the sound source, v is the speed of the sound in air, and vl is the velocity of the listener and vs is the velocity of the source.
00:23
We will use this convention depending on the motion of the listener and the source.
00:28
Here we're given that certain you are driving at a speed of 35 meters per second per cycle when you hear a siren coming from the police and that approaches you as it approaches you hear or you perceive the frequency to be at 1 ,370 hertz however you were not you were not the one being pursued by the police car and so it passes by you as it goes or as it continues to go past you, you are now perceiving the frequency of the sound as 1 ,330 hertz.
01:11
We want to find the speed of the police car.
01:16
So first is that we take the speed of sound to be equal to 343 meters per second.
01:24
So for the first case where the police car is approaching you, we have fl equals v and then notice that as the convention says, if the, if you are, you, the listener is moving towards the source...