Allen Dick wrote:

> >>>Centrifugal force for an extractor can be calculated with the formula
> f=mv²/r where f = force in newtons, m=mass in kgs, v=velocity in
> metres/second, and r= radius in metres.


> 2X RPM and force goes up 4X.
> 3X RPM and force goes up 9X.
> I.e. RPM has an exponential effect on force.
                  ^^^^^^^^^^^
Good post Allen! But please use the correct mathematical terminology:
RPM does NOT have an exponential effect on force -- the force varies
with the SQUARE of the speed ie RPM as in the formula you quote above.
Exponential implies that the "magical" number "e" = 2.71828.... appears
in the formula raised to a power that is dependant upon the RPM: if this
were so the force would increase with RPM much more dramatically than
indicated above!

> What a fantastic resource this is.
Absolutely! But what a shame we can't remove some of the dumb posts we
sent in ignorance or in haste: they all are there for future searchers
to find and shake their heads over!

Cheers Tony

--
Anthony N Morgan,
Førsteammanuensis
Institutt for Elektroteknikk
Høgskolen i Sør-Trøndelag
N-7004 Trondheim, Norway
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Tlf. 73 55 96 04
Fax. 73 55 95 81