# Not an actual hw problem, but it might as well be

#### lampshade

1. Homework Statement
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. Homework Equations

$$\frac{v^{2}}{r}$$

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 $$\omega^{2}*r$$ 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?

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#### Doc Al

Mentor
Looks good to me.

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