Consider standing waves in a pipe of length l-8.5 m containing a column of air. the speed of sound in the columns is vs 333 m/s. each of the standing wave images provided may represent a case for which one or both ends are open 13% part (a) select the image from the options provided showing the displacement of air particles for the third harmonic of a ?

58.8Hz

Explanation:

Harmonics or overtones are multiple integrals of the fundamental frequencies. Sound waves can occur both in closed pipes, open pipes and strings.

First we need to get the fundamental frequency in open pipes.

Note that frequency = velocity/wavelength

The length of the pipe (L) with fundamental frequency in term of its wavelength is ¶/2 (taking ¶ as wavelength)

L = ¶/2

¶ = 2L

Substituting this in the fundamental frequency formula

Fo = v/¶

Fo = v/2L

Since v = 333m/s

L = 8.5m

Fo = 333/2(8.5)

Fo = 333/17

Fo = 19.6Hz

This fundamental frequency will be the first harmonics

First overtone (f1) will be the second harmonics f1 = 2fo

Second overtone (f2) will then be third harmonics f2 = 3fo

f2 = 3×19.6

F2 = 58.8Hz

Third harmonic frequency will be 58.8Hz

*Check attachment for diagram

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i had a friend that had sleep paralysis and he told me a story one time where he was laying in bed and he couldn't move his body no matter how hard he tried and there was someone standing in the corner of his room coming towards him. he couldn't move and you can't "wake up" because you are already conscious. sometimes sleep paralysis can be triggered by frequent waking up during the night based off of multiple trips to the bathroom, or if you had ever been abused, sleep paralysis can start happening from things like that.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.