Question

High‑speed ultracentrifuges are useful devices to sediment materials quickly or to separate materials. An ultracentrifuge spins a small tube in a circle of radius 13.1 cm at 50000.0 rev/min. What is the centripetal force experienced by a sample that has a mass of 0.00310 kg?

Answer 1

Answer:

Fc = 7.14N

Explanation:

First of all, let's convert everything to the same unit system:

m = 0.0031kg     R = 13.1cm * 1m / 100cm = 0.131m      

ω = 50000 rev/min * 1rev /( 2π rad ) * 1min / 60s = 132.63 rad/s

Now we can calculate centripetal force as:

$Fc = m * \frac{V^2}{R} = m * \frac{(\omega*R)^2}{R}=m*R*\omega ^2$

Replacing the values we get the answer:

Fc = 7.14N