Tools and Reference

Calculation of G force for Centrifugation:  (5500 RPM is probably 2000 g in a microcentrifuge).

 

radial centrifugal force (RCF) = (1.12)(r)(rpm/1000)2, where r = radius in mm from spindle to sample bottom and rpm = revolutions per minute. 

The above equation can be rearranged to solve for RPM when centrifugation at particular g force is required. 

http://www.pitt.edu/~biohome/Dept/Frame/corndog.htm
http://www.hhmi.org/grants/awards/indiv/prof/hatfull.html
http://www.pitt.edu/~gfh/
http://www.pitt.edu/~gfh/