A cd has diameter of 120 millimeters. When playing audio, the angular speed varies to keep the linear speed constant where the disc is being read. When reading along the outer edge of the disc, the angular speed is about 206 rpm (revolutions per minute). Find the linear speed in meters/second. (round your answer to three decimal places.)

Respuesta :

we are given

A cd has diameter of 120 millimeters

so, d=120mm

so, firstly, we will find radius

[tex]r=\frac{d}{2}[/tex]

we can plug it

[tex]r=\frac{120}{2}mm[/tex]

[tex]r=60mm[/tex]

we know that

1mm=0.001m

so, we get

[tex]r=60*0.001m[/tex]

[tex]r=0.06m[/tex]

the angular speed is about 206 rpm

we know that

1 revolution =2pi radians

so, we get

[tex]w=200*2\pi rad/min[/tex]

now, we can change it into seconds

1 min =60 seconds

so, we get

[tex]w=200*2\pi *\frac{1}{60} rad/sec[/tex]

[tex]w=20.94395 rad/sec[/tex]

now, we can find linear speed(v)

we can use formula

v=w*r

so, we can plug values

and we get

[tex]v=20.94395*0.06 m/sec[/tex]

[tex]v=1.256637 m/sec[/tex]

so, linear speed is 1.257 m/sec............Answer

We will find that the linear speed of the outer rim of the cd is 1.29 m/s.

How to find the linear speed?

For the rotation pf an object of radius R that rotates with an angular speed ω the linear speed is:

S = |ω*R|

In this case, we know that:

R = 120mm/2 = 60mm

And the angular speed is 2*pi times the frequency, so we get:

ω = 2*3.14*(206 mîn^-1) = 1,293.68 min^-1

But we want the speed in meters/second, so we need to rewrite both of these quantities.

Knowing that:

  • 1mm = 10^-3 m
  • 1 min = 60s

R = 60mm = 60*(10^-3 m)  = 0.06m

ω = 1,293.68 min^-1 = ( 1,293.68/60) s^-1 = 21.56 s^-1

Then the linear speed is:

S = (0.06 m)*(21.56 s^-1) = 1.29 m/s

If you want to learn more about rotations, you can read:

https://brainly.com/question/9408577