Using sidereal time instead of 86400 seconds lowers the value by 0.001 % and is thus very small.
David David Jonsson, Sweden, phone callto:+46703000370 On Wed, Jan 12, 2011 at 2:54 PM, Mauro Lacy <ma...@lacy.com.ar> wrote: > > > > > > On 01/11/2011 04:43 PM, David Jonsson wrote: > >> Yes, under "effects of centripetal acceleration" which is by the way > >> an erroneous title since it should be centrifugal acceleration. > > > > Don't think so. In Newtonian terms, the acceleration's centripetal, > > caused by the centripetal force, which is provided by gravity. The > > "fictitious" centrifugal force is the outward-pointing acceleration of a > > uniformly moving non-rotating object (times its mass) which is observed > > from a rotating frame. However, in the rotating frame, the acceleration > > you're concerned with -- and the acceleration which leads to the > > "centrifugal force" -- is directed inward, and is "centripetal". > > If I didn't understand incorrectly, what David is saying is that when you > determine G empirically, by example by using a scale, centrifugal > acceleration must be discounted, because it's affecting the scale weights. > That is, the scale weights are subjected not only to gravitation, but also > to a centrifugal force, because they are inertial masses in rotation. And > also translation, by the way. To be extremely precise, you would also need > to consider the component of Earth's acceleration around the Sun, and > other accelerations. I suppose all those influences must be much smaller > than variations in G due to ambiental and geographical factors. The same > for the difference between sidereal and solar day, probably. > > > > > > >> > >> What I write there is in its entirety: > >> The denominator should use the sidereal day of 86 164.0905 seconds > >> instead of 86 400 since inertia is relative the stars and not the Sun. > >> David Jonsson 20:44, 11 January 2011 (UTC) --- Preceding unsigned > >> <http://en.wikipedia.org/wiki/Wikipedia:Signatures> comment added > >> by Davidjonsson <http://en.wikipedia.org/wiki/User:Davidjonsson> (talk > >> <http://en.wikipedia.org/wiki/User_talk:Davidjonsson> . contribs > >> <http://en.wikipedia.org/wiki/Special:Contributions/Davidjonsson>) > > > > That sure sounds right. (Just to be nit picky, I might argue that > > rotation is absolute, and the stars just provide some convenient distant > > markers; there's no reason I can see to think a centrifuge wouldn't work > > even if the universe were nearly empty.) > > > > > >> > >> David > >> > >> David Jonsson, Sweden, phone callto:+46703000370 > >> > >> > >> > >> On Tue, Jan 11, 2011 at 10:39 PM, Harry Veeder <hlvee...@yahoo.com > >> <mailto:hlvee...@yahoo.com>> wrote: > >> > >> Is this the right link? > >> Harry > >> > >> > >> *From:* David Jonsson <davidjonssonswe...@gmail.com > >> <mailto:davidjonssonswe...@gmail.com>> > >> *To:* vortex-l <vortex-l@eskimo.com > >> <mailto:vortex-l@eskimo.com>> > >> *Sent:* Tue, January 11, 2011 3:47:23 PM > >> *Subject:* [Vo]:g on Wikipedia erroneously defined > >> > >> Hi > >> > >> Ain't I right? > >> > http://en.wikipedia.org/wiki/Talk:Standard_gravity#effect_of_centripetal_acceleration > >> > >> Sidereal period should be used and not solar. > >> > >> Do you support a change? > >> > >> David > >> > >> David Jonsson, Sweden, phone callto:+46703000370 > >> > >> > >> > > > > >
