Paul Rutland The question was stated in RCF (that is, g) not in RPM, so it should not be necessary to square the values, if I understand the clearing factor k correctly.

k = 2.53 x 1011ln(Rmax/Rmin)/(RPM)2, where Rmax and Rmin are distances from the axis of rotation in cm,

and RCF = 11.17 x Rmax (RPM/1000)2

Substituting for (RPM)2 in the first equation shows that the clearing factor is inversely proportional to RCF.

Since clearing factor is directly proportional to time according to T = k/S, where S is Svedbergs of the particle and T is time to pellet, T is inversely proportional to RCF.

Yes, this should work. The centrifugation time to achieve clearance is inversely proportional to the g-force, all else (the nature of the sample and the dimensions of the rotor) being equal. If you halve the g-force, you should double the time.

I agree that it should work Adam B Shapiro but if we apply g = .0000284 x r x n2 then g =kn2 then the ratio of 130002 to 70002 is 169/49 which is more like 3.4 times as long for an equivalent g value

ps I was working in inches for the radius and formula

Paul Rutland The question was stated in RCF (that is, g) not in RPM, so it should not be necessary to square the values, if I understand the clearing factor k correctly.

k = 2.53 x 1011ln(Rmax/Rmin)/(RPM)2, where Rmax and Rmin are distances from the axis of rotation in cm,

and RCF = 11.17 x Rmax (RPM/1000)2

Substituting for (RPM)2 in the first equation shows that the clearing factor is inversely proportional to RCF.

Since clearing factor is directly proportional to time according to T = k/S, where S is Svedbergs of the particle and T is time to pellet, T is inversely proportional to RCF.

Thank you for that clear and accurate rationale Adam B Shapiro . You are correct. I was confused by the term speed in the question and without thinking converted the rcf ( as stated) to rpm. Good answer.

Thank you for such a succinct explanation Adam B Shapiro

Thank you so much sir Adam B Shapiro for helping me out with your great explanation.