Centrifuge Problem (Circular Motion)

In summary, a centrifuge rotates at 12000rpm and has a radius of 150mm. If you are inside of the centrifuge, the centripetal acceleration is 236871.61 m/s2.
  • #1
GoodOldLimbo
7
0

Homework Statement



A Centrifuge rotates at 12000rpm. What is this in radians per second?

If the radius of this centrifuge is 150mm, what is the centripetal acceleration?

Homework Equations



v2 / r

v = rω

a = rω2


The Attempt at a Solution



First I converted the 12000rpm to 1256.64 rad/sec.

12000 / 60 = 200 Rev. per minute.

200 x 2∏ = 1256. 64 rad/sec

Onto the centripetal acceleration, I was given a = rω2

a = 0.15 x 1256.642

a= 236871.61 m/s2

I'm just a little thrown off by how incredibly large the number is and I don't really have any idea of how a centrifuge usually moves. Any help?

Would be much appreciated.
 
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  • #2
GoodOldLimbo said:

Homework Statement



A Centrifuge rotates at 12000rpm. What is this in radians per second?

If the radius of this centrifuge is 150mm, what is the centripetal acceleration?

Homework Equations



v2 / r

v = rω

a = rω2


The Attempt at a Solution



First I converted the 12000rpm to 1256.64 rad/sec.

12000 / 60 = 200 Rev. per [STRIKE]minute [/STRIKE]second

200 x 2∏ = 1256. 64 rad/sec

Onto the centripetal acceleration, I was given a = rω2

a = 0.15 x 1256.642

a= 236871.61 m/s2

I'm just a little thrown off by how incredibly large the number is and I don't really have any idea of how a centrifuge usually moves. Any help?

Would be much appreciated.

Welcome to the PF.

I only see one problem in your work, and it's just a simple typo that doesn't change the numbers. See where I fixed it in the quoted text above.

And yes, the acceleration does seem high, but after all that's what centrifuges are for. I used Google to look up some typical specs on labratory-grade centrifuges to see if the acceleration number you calculated is reasonable. The 12,000 rpm given number is pretty fast for the centrifuges that I looked up, but the size is in the typical range.

Convert your acceleration into the number of g's (g = 9.8m/s^2), and compare your answer to what you find on Google. Post what you find so we can see what you are getting...
 
  • #3
That acceleration value is fine for a centrifuge. And it is still far away from their limits.
 

What is a centrifuge?

A centrifuge is a laboratory device that uses centrifugal force to separate particles of different densities within a liquid. It consists of a rotating container, called a rotor, that spins at high speeds, causing the denser particles to move towards the outside of the container while the less dense particles stay closer to the center.

How does a centrifuge work?

A centrifuge works by spinning the rotor at high speeds, typically thousands of revolutions per minute (RPM). This causes the liquid sample to experience a centrifugal force that is much greater than the force of gravity. As a result, the denser particles in the sample move towards the outside of the rotor, where they can be collected and separated from the rest of the sample.

What is the purpose of a centrifuge?

The main purpose of a centrifuge is to separate particles of different densities within a liquid sample. This can be useful in a variety of scientific fields, such as biology, chemistry, and medicine, for processes such as cell separation, DNA extraction, and blood component separation.

What is the difference between a fixed-angle and a swing-bucket centrifuge?

A fixed-angle centrifuge has a rotor that remains at a fixed angle during operation, while a swing-bucket centrifuge has a rotor that can swing out to a horizontal position during operation. Fixed-angle centrifuges are better for pelleting, or collecting particles at the bottom of the tube, while swing-bucket centrifuges are better for separating components from a sample.

What safety precautions should be taken when using a centrifuge?

Some safety precautions that should be taken when using a centrifuge include wearing appropriate personal protective equipment, ensuring the rotor is properly balanced, and following manufacturer's instructions for maximum speed and load capacity. It is also important to regularly inspect and maintain the centrifuge to prevent malfunctions or accidents.

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