00:02
So we're told that room temperature is 20 degrees celsius, and the frequency of sound in this problem is 686 hertz.
00:19
And they're both emitting sound waves along the x -axis.
00:29
These are in phase, which means that they are identical sources, in phase with the same.
00:38
Amplitude.
00:41
So in part a, we're looking for the smallest distance that will lead to destructive interference.
00:49
Identical sources destructive interference would mean that delta x equals lambda m plus one half, where m is zero.
01:07
Now, the speed of sound is three.
01:15
343 meters per second.
01:20
Speed equals wavelength times frequency.
01:26
So wavelength is speed over frequency.
01:35
So delta x would be one half of the speed over the frequency.
01:42
So let's put that into a calculator.
01:46
1 1⁄2 times speed, which is 343, over frequency, which is 686.
01:57
And that gives us 0 .25 meters.
02:15
All right...