What Is the Centripetal Acceleration at Different Points on a Rotating CD-ROM?

AI Thread Summary
The discussion revolves around calculating centripetal acceleration at different points on a rotating CD-ROM. Initially, centripetal acceleration is given as 264 m/s² at a radius of 0.0330 m, prompting the need to find acceleration at 0.0702 m. The user attempts to calculate velocity using the formula ac = v²/r, but realizes that velocity is not constant due to the nature of rotation. They are advised to consider angular velocity for accurate calculations, as it remains constant during rotation. The conversation highlights the importance of understanding the relationship between linear and angular velocity in rotational motion.
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1. A computer is reading data from a rotating CD-ROM. At a point that is 0.0330 m from the center of the disk, the centripetal acceleration is 264 m/s2. What is the centripetal acceleration at a point that is 0.0702 m from the center of the disc?



2. ac=v2/r



3. So my thoughts here are that it should be assumed that the velocity is constant. So I need to fine that velocity for the known radius and acceleration with the equation about. After I find the velocity, I can plug it into the equation with the new radius and find the acceleration that way.
ac=v2/r
264=v2/.0330
v2=8.712 m/s
v=2.95161 m/s

then plugging that into the equation with the other radius
ac=v2/r
ac=8.712/.0702
ac=124.10256 m/s2

This is not the right answer for my homework though. Not sure what I am doing wrong. Anyone know?
 
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well...the disc is rotating...so v is NOT constant. However, for constant rotation, angular velocity is constant. Use the relation between that and v, and modify your equation for acceleration.
 
ok, I understand now that the velocity is not constant. I don't believe we have covered angular velocity yet in class, unless I am just overlooking it. How do you do that? I did set up a proportion though with the velocity and radius and got it correct.
 

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