Question

The diameter of
a DVD is approximately 12 centimeters. The drive
motor of the DVD player is controlled to rotate
precisely between 200 and 500 revolutions per minute,
depending on what track is being read.
(a) Find an interval for the angular speed of a DVD as
it rotates.
(b) Find an interval for the linear speed of a point on
the outermost track as the DVD rotates.

Answer 1

rpms ARE angular speeds, right?

Answer 2

yes

Answer 3

the linear speed is simply how fast a given point on the circumference of a circle is moving

Answer 4

C = dpi = 12pi in this case

we move 12pi with each "r" of the rpm :)

Answer 5

but the between 200 and 500 is throwing me off, what do i do there?

Answer 6

200 to 500 is the interval of angular speed, as far as i can deduce

Answer 7

12pi*200 is your lower linear speed

12pi*500 is your upper linear speed

Answer 8

ok and the answer is?

Answer 9

I need both angular and linear.

Answer 10

those are the answers; i just dont know what format you need them in so I figure you could work that part out

Answer 11

My friend somehow got ([400, 1000] rad/min] and [2400, 6000 cm/min]) for the answer

Answer 12

the 2400 6000 looks to be good

Answer 13

the rads part i think might have to dbl chk

Answer 14

2pi rads the angle that sweeps out a full circle

Answer 15

so id venture to say those others need a pi in them

Answer 16

ahhh okay. Thanks man I figured it, well with you help haha
^_^

Answer 17

:) good luck

Answer 18

Thanks ^_^