How long does one revolution take for a rotating cd

Question

I have the question "When a cd rotates at an angular speed of 10.5 rads^-1, how long does one revolution take ?"

Here is my attempt.

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Is this correct ?

ROughly speaking, it is perfect. Of course $2\pi/10.5$ is not precisely 0.6, but you have the right idea. — Mark Fischler, Nov 30 '16 at 19:19

score 2 · Accepted Answer · answered Nov 30 '16 at 19:27

2

0.59839860068 would be the result of the division, but it needs to be rounded to the least numerical accuracy of measurement values. 2 and $\pi$ are not measurement values, but 10.5 is.

10.5 has 3 "Significant figures".

So your answer also has to have 3 significant figures. The leading 0. do not count, so 0.598 would be the correct answer.

answered Nov 30 '16 at 19:27

Pieter21

3,475

Thank you (: I understand now. – Dan Nov 30 '16 at 19:28

How long does one revolution take for a rotating cd

1 Answers1