A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Such a device is used in medical laboratories, for instance, to cause the more dense red blood cells to settle through the less dense blood serum and collect at the bottom of the container. Suppose the centripetal acceleration of the sample is 8.75 x 103 times as large as the acceleration due to gravity. How many revolutions per minute is the sample making, if it is located at a radius of 2.80 cm from the axis of rotation?(adsbygoogle = window.adsbygoogle || []).push({});

1st - figured out the accelration = 8.75E3 * 9.8 = 155 m/s

2nd converted it to m/hour 155 m/s * 60s/h = 9300 m/h

3rd calculated the total distance of 1 rotation = 2*.28*pi = 1.76 m

4th divided velocity / distance = 5284 rpm

But it says my answer is incorrect. What am I doing wrong (beside working on physics homework at 3am)?

Thanks!

-Serena

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# Homework Help: How many revolutions per minute is the sample making

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