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Homework Help: Not an actual hw problem, but it might as well be

  1. Jul 12, 2007 #1
    1. The problem statement, all variables and given/known data
    Basically I bought a new 7200 rpm hard drive and I was curious about it since it is a 2.5 inch notebook hard drive. What I was wondering was how many g's were pulled at the edge of the disk while it spun at 7200 rpm

    2. Relevant equations


    I'm just gonna make up a number and say the radius is 1.25 inches on a 2.5 inch drive so lets say the radius of the spinning disk then is 0.03175 m

    3. The attempt at a solution

    so basically what I then did was
    7200 rpm where 1 revolution is 2pi rad
    7200*2pi rad is about 45238.9342 rad/min
    divide by 60 to convert to seconds
    753.982237 s^-1
    then [tex]\omega^{2}*r[/tex] becomes my centripetal acceleration, right?

    Therefore assuming a radius of .03175 the edge of the disk is feeling an acceleration of 753.982237^2 * 0.03175 = 18049.5325 m/s^2

    which would be roughly 1841.78903 g?

    ugh I'm embarrassed that I"m not confident about this answer. Does everything look good?
  2. jcsd
  3. Jul 12, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Looks good to me.
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