Centrifuge Revolution Calculation

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To determine the revolutions per second of a centrifuge, the force acting on a red blood cell can be used alongside the equation F = m(v^2/r). The mass of the red blood cell is 3.0e-16 kg, and the force is 4.0e-11 N. By calculating the velocity and then dividing it by the circumference of the centrifuge, which has a radius of 16.0 cm, the answer can be converted to revolutions per second. This method confirms that maintaining units in kilograms is essential for accurate calculations. Ultimately, understanding the relationship between velocity and circumference is key to solving the problem.
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A sample of blood is placed in a centrifuge of radius 16.0 cm. The mass of a red blood cell is 3.0e-16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0e-11 N. At how many revolutions per second should the centrifuge be operated?

I can figure out the velocity... but the answer needs to be in revolutions per second. Would I just divide the velocity by the circumference of the centrifuge??
 
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je55ica7 said:
I can figure out the velocity... but the answer needs to be in revolutions per second. Would I just divide the velocity by the circumference of the centrifuge??
That's correct.
 
Ok, I figured out the problem using F=m(v^2/r). I got the right answer when I kept the mass in kg and solved for v. How could that be right if the answer had to be in rev/s? I don't get it...
 
Calculate the circumference and you'll get it. :wink:
 
Lol

Soooo sneaky... hehe
 

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