How Do You Calculate the Sedimentation Coefficient of Escherichia coli?

[quietviolence]

Homework Statement

Escherichia coli data:
molecular weight = 74000g/mol
specific volume = 0.737cm³/g
temperature = 293 K

In a dilute aqueous buffer (0.02M potassium phosphate) at 293.75 K
speed of rotation = 56050 rpm

gave the following results:

Time (min)...x_1/2
0.....5.9
20...6
40...6.1
60...6.2
80...6.3
100.....6.4
120.... 6.5
140.....6.6

Homework Equations

This is the equation given to us:

M=(RTs)/(D(1-($$\rho$$ _f *V _o))

The Attempt at a Solution

I used an R value of 8.31m²kgmol^-1s^-2K^-1

I rearranged the equation to equal s

However, I got stuck at $$\rho$$_f*V_o. Using the $$\rho$$ and V given in the question results in a division by 0.

Could someone explain to me how I find $$\rho$$ _f and V _o? I don't need anyone to solve the question, I would like to do that on my own.

 

[quietviolence]

I'm sorry for the terrible equations.
The rho is supposed to be rho with a subscript f, and V is V subscript o