Re: Is the state of 'free fall' inertial?

On Thu, 28 May 2009 09:31:15 -0700 (PDT), "Sue..." <suzysewnshow@xxxxxxxxxxxx>
wrote:

On May 27, 7:10 pm, hw@..(Henry Wilson, DSc) wrote:
On Wed, 27 May 2009 04:58:47 -0700 (PDT), "Sue..." <suzysewns...@xxxxxxxxxxxx>
wrote:

On May 27, 4:34 am, hw@..(Henry Wilson, DSc) wrote:

=================

Is the state of 'free fall' inertial?

<< Einstein in the years following 1905 to seek a broader and
more coherent context for the laws of physics. In the introduction
of his 1916 review paper on general relativity he wrote:

" The weakness of the principle of inertia lies in this, that
it involves an argument in a circle: a mass moves without
acceleration if it is sufficiently far from other bodies; we
know that it is sufficiently far from other bodies only by
the fact that it moves without acceleration."

He was obviously just as confused about this as anyone else.

We could equally well substitute [has the greatest lapse of
proper time] for [is sufficiently far from other bodies]. In either
case the point is the same: special relativity postulates the
existence of inertial frames and assigns to them a preferred
role, but it gives no a priori way of establishing the correct
mapping between this concept and anything in reality. >>
http://www.mathpages.com/rr/s4-07/4-07.htm

Well that says a lot...  :)

"Universality of Free Fall and General Relativity"

?Weak Equivalence Principle (WEP): inertial and gravitational
masses are proportional (or: mass and weight are proportional). Or:
falling objects follow the same trajectory (University of Free Fall,
UFF).

?Einstein Equivalence Principle (EEP): 1. WEP is valid; 2. any
non-gravitational experiment gives the same results in freely falling
frames; 3. The results are independent of when and where in the
Universe the experiment is done. Thus physical constants should also
be the same always and everywhere. EEP probably also implies that
gravity can be described in terms of a curved spacetime geometry.

...another load of meaningless drivel....

?Strong Equivalence Principle: Objects with self-gravity (e.g. stars,
planets and moons) also fall in the same way. That would not be true
if attraction was different for the gravitational binding energy.
?It is now questioned whether dark matter and energy should also fall
in the same way as ordinary, baryonic matter. >>
http://www.kfki.hu/eotvos/UFFEotvos4.pdf

It's embarrassing to read this stuff________
_______________________________________

Why  I asked, is that any object in remote space is in a state of free fall.

Then you are "obviously just as confused about this as anyone else."

No I'm not. Anything floating around space is falling freely somewhere.
It has been claimed here that free fall is inertial....yet even in remote space
an object will be accelerating towards something else.
In that case, anything with a finite length will be 'stretchrd' slightly since
the end nearest the attracting body will experience more 'pull' than the
opposite one. Would that not be true?

So in reality, a vertical rod that is free falling towards Earth could be
equiped with a strain guage that could monitor its extension, from which could
be made an estimate of the gravitational gradient at any point as it traveled.


An object falling towards Earth is in a state of free fall. Objects in free
fall feel no acceleration yet an observer on the moon would certainly see a
falling object ACCELERATING towards the Earth's surface.  

An orbiting object has acceleration yet is in free fall.

I say this paradox demonstrates the basic flaw in the EP.

The equations:
a = F/m
and
a = d2x/dt2
define acceleration in two different ways.

But equating d2x/dt2=F/m introduces contradictions.

Well... I disagree with Einstein.

OK, I will be polite then.

An object moves in a straight line if the distribution
of mass in a region is homogeneous. That is the
condition where acceleration can be measured by
spatial displacement.

point taken.

A free falling observer still has the gravity force acting on him yet is
supposed to be inertial...ie., has no acceleration..
In contrast, he feels no force but can observe his own acceleration.

AFAIK you can't escape gravity. It is a component of
the inertial mechanism if you have no preferred frames.

What I cannot fathom is why the same gravity force acts whether or not an
object is free falling or propped up on a pole.
If an electron is 'free falling' in an electrostatic field, its acceleration
tends to REDUCE the field.

http://en.wikipedia.org/wiki/Preferred_frame#No_preferred_frames

Sue...


.

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