Hello Ulrich, is it not important to bring into the game the satellite's velocity in relation to earth (on a tangential straight path deviated by gravitational acceleration)?
73, Arnold, DK2WT On Sun, 27 May 2007 19:59:22 +0200, Ulrich Bangert wrote: >Didier, >> gravitational forces, so do objects in Lagrange points. These points >> represent areas where the centrifugal forces compensate for >> gravity.... >I am almost sure that this will again produce me a lot of trouble in >answering a lot of people but the idea that there are centrifugal forces >which compensate for gravity are one of the BIGGEST misconcepts that one >may have in physics at all although it is quite common and you may find >statements like that eben in (bad) physics textbooks. >Centrifugal forces are so called fictitious forces which are only >observed from within accelerated systems. Normal physics is done in >inertial systems. In an inertial system consisting of earth and an >satellite there are only TWO forces available: The gravity force by >which earth attracts the satellite and the gravitational force by which >the satellite attracts earth. They are of the same magnitude but of >opposite direction. That is the reason why the "sum of forces" is zero >for the closed system consisting of earth and satellite. There is no >place for any other force like centrifugal or so because there is no >counterforce available that would make the sum of forces zero i case a >centrifugal force would exist. In case you like to discuss it a bit >please go on but be prepared that I will to blow your arguments into >little bits. A good idea to start with is to look after what Newton's >first law is saying about the behaviour of a body for which all forces >compensate each other. Is that what a satellite does??? >73 Ulrich, DF6JB >> -----Ursprüngliche Nachricht----- >> Von: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] Im Auftrag von Didier Juges >> Gesendet: Sonntag, 27. Mai 2007 16:54 >> An: Discussion of precise time and frequency measurement >> Betreff: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity >> >> >> For the same reason that a satellite in free fall is still subject to >> gravitational forces, so do objects in Lagrange points. These points >> represent areas where the centrifugal forces compensate for >> gravity from >> two objects instead of one for a regular satellite. The only >> way to be >> free from gravitation is infinite distance from mass, until someone >> actually invents the famous gravitational shield :-) I hope >> it comes in >> spray form... >> >> Didier >> >> Neville Michie wrote: >> > Look up Lagrangian points on Wikipedia. >> > There are points of zero gravitational force, about our planet. What >> > is more, these points are stationary with respect to Earth, so >> > Doppler effects would be zero. >> > As the distance from Sun to Earth to Moon varies through >> the year it >> > follows that the distance from Earth of these points must >> vary on a >> > small scale. >> > These points are good for satelites as the orbit never decays. >> > cheers, Neville Michie >> > >> > >> >> _______________________________________________ >> >> time-nuts mailing list >> >> time-nuts@febo.com >> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
