Paul Dundon’s Weblog


A little cheese and a little whine

You spin me right round

The series “Defying Gravity” features a spaceship which generates “artificial gravity” by spinning parts of its body around a central axis. The question naturally occurs:- how fast would a cylinder have to spin to generate a centripetal force equivalent to gravity?

It turns out that the answer, in rpm, is very close to 30 times the reciprocal of the root of the radius (ie 30/sqrt(r)).

The derivation is here (PDF – only way I can get the equations to show reliably).


Filed under: Maths

2 Responses

  1. John'z Place says:


    I don’t know if you’ve come across this reading but if you’re really interested in where our planet is on “Taming Gravity” you might want to read this Popular Mechanics Oct 1999 issue on Dr. Ning Li and her “A/C Gravity”.

    The article is titled “Taming Gravity” appropriately.

    The article does a very good job of explaining Dr. Ning Li’s A/C Gravity. It is a must read for anyone interested in where our planet is on the subject of “Taming Gravity”!

    The more people know this is there the faster things will happen, no?

    Just do a post on it to help move it along!


  2. […] A comment (from John Z) on an earlier post highlights some interesting research on anti-gravity. Unfortunately, I can find nothing relating […]

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My Bookshelf

The Golden Bough
The Value of Nothing
The Fire
A Wolf at the Table
Devil Bones

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