Disk Problem

[johnjones]

For a hard disk with platters that are 3.5 inches in diameter, what is the linear speed (in km/h) of the outer edge of the platter? Calculate the answer for both 7,200 and 10,000 RPM.

Please help, I have no clue what to do? Thanks!

 

[stapel]

Find the circumference of a platter. This is the linear distance covered in one revolution.

Multiply by the number of revolutions per minute. This gives you "inches per minute".

Then convert to kilometers per hour. (Your book should provide conversion factors between inches and centimeters, or between miles and kilometers -- or both --; use whichever you prefer.)

If you get stuck, or would like your answer checked, please reply showing all of your steps. Thank you.

Eliz.