00:01
Alright, so let's say we have a frequency generator and it's generating waves.
00:06
Let's see if i can draw them.
00:08
Two, three.
00:12
And it's connected to a hanging mass.
00:16
And we're told the length of this vibrating section is 2 .3 meters.
00:22
And we can see readily from this picture that the wavelength is going to be, basically, we can write as 2l over 5, so 0 .92 meters.
00:34
And we're told that we only observe harmonics for a mass of 25 kilograms or 36 kilograms.
00:48
And so we want to know what then is the frequency of the generator.
00:53
So the linear mass density is 0 .002 kilograms per cubic meter.
00:57
So what we'll have is the speed of sound is going to be the square root of the tension, which is mg over the linear mass density.
01:07
And this should be the frequency of the generator times the wavelength of the particular mode we're talking about.
01:14
And so what we'll have is for our first mass, 25 kilograms.
01:20
If we calculate the speed of sound for our first mass, we'll call this m1...