Centripetal acceleration in separating protein

[tvtokyo]

Homework Statement

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?

Homework Equations

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

The Attempt at a Solution

Terminal velocity = (mω²)/k_r * (1 - ρ_fluid/ρ)
But this question there is a lot of unknown variables so how to we approach it ? Thank you!

 

[Andrew Mason]

Homework Statement

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?

Homework Equations

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

The Attempt at a Solution

Terminal velocity = (mω²)/k_r * (1 - ρ_fluid/ρ)
But this question there is a lot of unknown variables so how to we approach it ? Thank you!

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