Centripetal acceleration in separating protein

1. Oct 2, 2015

tvtokyo

1. The problem statement, all variables and given/known data
Two protein having same density 1.35 g /cm^3 but with different diameter 4nm and 5nm. They are mixed at the top of a centrifuge tube that is of length 1cm. What is the centripetal acceleration needed to separate them before they move to the end of the tube?

2. Relevant equations
Do we use V^2 = (Vo)2 + 2as where s = 0.01m and Vo = 0 ? where a = centripetal acceleration and V = terminal velocity??

3. The attempt at a solution
Terminal velocity = (mω2)/kr * (1 - ρfluid/ρ)
But this question there is a lot of unknown variables so how to we approach it ? Thank you!

2. Oct 3, 2015

Andrew Mason

While this involves a rather basic concept of centripetal force it arises in a very specialised application. Most of us on this board do not have working familiarity with centrifuges, tubes etc. I expect that protein separation is a very common use for centrifuges in biology labs. If you want a physics answer you have to give us a bit of background explaining exactly the set up here and give us the formulas that you are working with. It sounds like a combination of rotational, friction, and fluid dynamics.

AM

Last edited: Oct 3, 2015