Acceleration and rotation of centrifuge

[aligass2004]

Homework Statement

A typical laboratory centrifuge rotates at 4200 rpm. Test tubes have to be placed into a centrifuge very carefully because of the very large accelerators. a.) What is the acceleration at the end of a test tube that is 11 cm from the axis of rotation? b.) For comparison, what is the magnitude of the acceleration a test tube would experience if dropped from a height of .8 m and stopped in a 1.0 ms long encounter with a hard floor?

Homework Equations

w=2pi radians (f)
a = w^2 r

The Attempt at a Solution

I tried finding the frequency, then using the frequency to find w, which I got to be 439.823. Then I tried finding a, which I got to be 48.381.

 

[PhanthomJay]

Homework Statement

A typical laboratory centrifuge rotates at 4200 rpm. Test tubes have to be placed into a centrifuge very carefully because of the very large accelerators. a.) What is the acceleration at the end of a test tube that is 11 cm from the axis of rotation? b.) For comparison, what is the magnitude of the acceleration a test tube would experience if dropped from a height of .8 m and stopped in a 1.0 ms long encounter with a hard floor?

Homework Equations

w=2pi radians (f)
a = w^2 r

The Attempt at a Solution

I tried finding the frequency, then using the frequency to find w, which I got to be 439.823. Then I tried finding a, which I got to be 48.381.

you forgot to square the w term!

 

[queenyv2005]

use T= 2(pi)(r)/v to get the velocity and then use a= v^2/r to get part a

 

[dlgoff]

And be sure to include your units.

 

[aligass2004]

I did forget to square the w term. I got 21278.87m/s^2 for part a.

 

[aligass2004]

For part b, I thought to just use Yf = Yi + Viy(t) + 1/2 (a) (t^2). I got 1.6E6 m/s^2, but it said it was wrong.