Although the vocal tract is quite complicated, we can make a simple model of it as an open-closed tube extending from the opening of the mouth to the diaphragm, the large muscle separating the abdomen and the chest cavity. What is the length of this tube if its fundamental frequency equals a typical speech frequency of 200 Hz?

0.429m

Explanation: fundamental frequency is 200 Hz and the speed of sound in air is 343 m/s.

Recall that v = fλ

Where v = speed of sound = 343 m/s

f = frequency of sound = 200 Hz

λ = wavelength of sound =?

By substituting the parameters, we have that

343 = 200 × λ

λ = 343/ 200

λ = 1.715m.

Since the vocal tract is assumed to be an open-closed tube, the relationship between the length of air and wavelength at fundamental frequency is given below as

L = λ/ 4

But λ = 1.715m

L = 1.715/4

L = 0.429m

the bal will not change its velocity.

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