)music. when a person sings, his or her vocal cords vibrate in a repetitive pattern that has the same frequency as the note that is sung. if someone sings the note b flat, which has a frequency of 466 hz, how much time does it take the person’s vocal cords to vibrate through one complete cycle, and what is the angular frequency of the cords? (b) hearing. when sound waves strike the eardrum, this membrane vibrates with the same frequency as the sound. the highest pitch that young humans can hear has a period of 50.0 ms. what are the frequency and angular frequency of the vibrating eardrum for this sound? (c) vision. when light having vibrations with angular frequency ranging from 2.7 * 1015 rad> s to 4.7 * 1015 rad> s strikes the retina of the eye, it stimulates the receptor cells there and is perceived as visible light. what are the limits of the period and frequency of this light? (d) ultrasound. high-frequency sound waves (ultrasound) are used to probe the interior of the body, much as x rays do. to detect small objects such as tumors, a frequency of around 5.0 mhz is used. what are the period and angular frequency of the molecular vibrations caused by this pulse of sound?

(a) 0.0021 s, 2926.5 rad/s

The frequency of the B note is

The time taken to make one complete cycle is equal to the period of the wave, which is the reciprocal of the frequency:

The angular frequency instead is given by

And substituting

f = 466 Hz

We find

(b) 20 Hz, 125.6 rad/s

In this case, the period of the sound wave is

T = 50.0 ms = 0.050 s

So the frequency is equal to the reciprocal of the period:

While the angular frequency is given by:

(c)

The minimum angular frequency of the light wave is

so the corresponding frequency is

and the period is the reciprocal of the frequency:

The maximum angular frequency of the light wave is

so the corresponding frequency is

and the period is the reciprocal of the frequency:

(d)

In this case, the frequency is

So the period in this case is

While the angular frequency is given by

if the forces acting on an object are unbalanced, the object will accelerate in the direction of the net force on the object.

explanation:

this is best explained by having an understanding of newton's second law, which states that f=ma. you see, when the forces are unbalanced, net force (sum of all forces) is not zero. therefore making it necessary for the object to have an acceleration in the direction of the net force.

be subject to a force andchange its motion