00:01
So this question we're asked to write the displacement equation for a wave, for a sinusoidal traveling wave, given that it's traveling along the negative x direction, and it has amplitude of 0 .01 meters, frequency 550 hertz, and a speed of 330 meters per second.
00:21
So that's write down everything that we're given.
00:23
So we're told that it's in the negative x direction.
00:30
So negative x direction we're told that it has a velocity of 330 meters per second that it has frequency of 550 hertz and it has an amplitude of 0 .01 meters so using all this we can determine the equation that describes the displacement of the wave.
01:20
So the base of this question is the equation that given in the book for the just for the wide displacement of the wave which is equal to the amplitude sign of kx plus or minus omega t and then we're going to assume there's no phase difference or phase term in the in the argument of the sign function.
01:47
So first of all since it's in the negative direction in the book negative negative extraction so i'm plot we're told that negative extraction implies that it's going to be kx plus omega t since plus always describes something and moving in the in the left direction and minus describes it moving in the in the right direction so that so that so now we have the sign of our of our of our function and we're also we know the amplitude that's just given to us so now we just need to determine what k in omega -half.
02:22
So we know that k is the wave number is equal to two pi over lambda and we don't have lambda but we can find it so we know that c is equal to f lambda which implies that lambda is equal to c over f which is equal to 330 meters per second over 550 hertz and if we work this out this is equal to 0 .6 meters so that means the wave number is equal to 2 2 pi over 0 .6 meters, which is equal to, if we work it out, it's equal to 10 .5 per meter.
03:07
So now that we have the wave number, all we need to find is the angular frequency...