00:01
In this problem on the topic of waves, we are told that a sinusoidal longitudinal wave is sent along a long coil spring.
00:06
The wave travels in the negative x direction, and the source has frequency 25 hertz.
00:12
At any instant, the distance between successive points of maximum expansion in the spring is 24 centimeters.
00:18
The maximum longitudinal displacement of a particle in the spring is 0 .3 centimeters, and at x is equal to 0, there is zero displacement at t is equal to 0.
00:28
The wave has a form of sm cosine kx plus or minus omega -t.
00:35
We want to find the displacement amplitude sm, the value for k -o -m, the wave speed, and the choice of sine for omega.
00:45
So the wave can be written as a displacement function, s of x and t, as the displacement amplitude sm times the cosine of the wave number k times the displacement of the wave x minus the angular frequency omega times time t so for part a the amplitude sm is equal to the maximum displacement and the maximum displacement is 0 .3 centimeters the angular wave number k can be gotten from the wavelength and the wavelength is given to be 24 centimeters and so we can find k, which is 2 pi over lambda.
01:43
So the wave number k is 0 .26 per centimeter...