Radi Khrapko:

So, you did not define mass (of a moving body). So, you cannot say

Are you dense or just a crackpot? I've answered this and when you care
to address that answer or else stop asking the question, I'll consider
responding to any other question I haven't answered.

Gauge wrote:
: Joe Fischer wrote
: I will comment that the second edition, if that
: was what page 248 was from uses the made up word
: "momenergy", which is moronic.
:
: So now you're insulting the authors huh?

Whoever made up that word, yes, it is not
needed, it is not a physical entity, and it duplicates
and complicates the concepts of momentum and energy.

: Little boys make up words and then call it physics,
: and frankly I doubt if Wheeler or Taylor wrote those
: words, they were probably written by a graduate student.
:
: Nope. Taylor and Wheeler did. And inventing words is what physicists
: do when explaining things or giving names to new quantities etc.

You don't know that, and it is certain that
at least one of them has a different opinion of
relativistic mass than you.

Your problem is double, you see nothing wrong
with using the term relativistic mass, which one of
those authors or both called abominable, plus
you are unable to see the necessity of all physicists
using the same word to mean invariant rest mass and
a distinctive other word to mean coordinate dependent
energy.

: Before a collision no "energy" exists, there is
: simply the rest mass, and that is why mass is considered
: to be invariant, and not velocity dependent.
:
: You've never really understood the velocity dependance of mass.

Look, mass is measured in it's own rest frame
with precision, bu comparing to a known standard, in
a vacuum chamber.
You have been away from physics too long and
now come back trying to impose your skewed views on
others.
Mass unqualified must mean quantity of matter,
which cannot change without a collision, that is why
it is called invariant mass by physicists, and why
thinking physicists will consider the reasons for
calling it invariant, and agree.

: You're
: stuck in Newton's world and you can't find your way out.

Your opinion is ignorant of the thousands of
posts I have made regarding gravity.

: What were inherent properties in Newtonian physics
: are no longer inherent properties in relativity.

As far as quantity of matter, called mass goes,
not too much.
And understanding of radioactive decay is new,
and equivalent energy is new, but you are trying to
call math tools something they are not.

: The length of a rod varies with speed. The
: rate at which a clock ticks varies with speed -

Compared to what? I have come to think
that you ask questions just to find out the opinion
of others so you can argue the opposite.

: and a body's inertia
: mass varies with speed and a body's weight varies with speed etc etc
: etc etc

Which is stupid, put on the pointy hat and
go stand in the corner till you learn that the
quantity of matter does not change without a
collision or spontaneous decomposition.

: Rest mass is "resistance to acceleration",
: in the rest frame of the object.
:
: Inertial mass is and that's velocity dependant - rest mass is just
: inertial mass at low speed.

Inertia is what produces the effects that
allow measurement of quantity of matter by comparison
with an established standard.
For that reason inertial mass should have
the same meaning as rest mass, and if you want to
play games with numbers, which is all you do in
a text like Spacetime Physics, then at least have
the intelligence and desire to avoid confusion by
calling your _calculated_ value something else
than unqualified mass.
Mass can only be measured in it's own rest
frame, all else is calculation or measurement of
the final products _after_ a collision, which
means after the velocity has drastically changed,
and the object probably no longer exists in a
form thst can be identified as the products of
the interaction of the collision and totally
new and different types of matter, measured at
the center of a new and different system.

: Motion has to be technically described as
: "relative motion", but the Earth has always been
: a convenient rigid and stationary reference that
: has been used for motion, and the relative part
: is not needed in problems on the surface.
:
: So "motion" by itself has no meaning, and
: the kinetic energy or momentum have no meaning
: for a single object in space.
:
: Everyone who knows relativity knows very well that when it is said
: that a particle has a given velocity then its with respect to the
: frame of referance in which the observer is in.

It is possible to do math anyway you want if
it gives the right answers.
But a collision only happens in the reference
frame common to both the colliding objects, the
observer has nothing to do with the collision, and
different observers can have widely differing values
from measurements.
The study of relativity is precisely for the
opposite purpose than the way you use it, it is to
establish a method that will allow all observers
to agree, and obviously you are using it solely
to disagree.

: If you see an author
: state in a text "A rod with rest lenght L is moving at 0.9 c. Find the
: length of the rod." then the meaning is obvious. The speed is relative
: to the observer - and the reader is always to take the position of the
: observer in such cases.

So is the rod the same length as the observer finds,
and why would a man say that physics is the same everywhere
and then say that the length of the rod depends on who is
looking at it.
Why would a physicist care what an observer sees,
a physicist should be only interested in the intrinsic
length of the rod.

: That is why saying mass increases with velocity
: is stupid, and called abominable by one author.
:
: By THAT author. Not all authors.

And by everybody else who knows anything about
relativity physics.

: It gives the wrong impression ..
:
: Not to someone who knows physics.

They already know that the intrinsic properties
of matter do not change every time a different person
looks at them.

: So to have physics not be complicated,
: and to work in all cases, the concept of
: mass changing with velocity must be abandoned.
:
: Total nonsense. This is like you're saying that since the rate at
: which a clock ticks is a function of its speed relative to the
: observer that that concept of time dilation must be abandonded. Then
: again you've never displayed an understanding of length contraction
: and time dilation and I've asked you many times.

I have no interest in observer viewpoints,
draftsmen make drawings of real objects, physicists
work with objects that do not change because other
people look at them.
Does an object cease to exist because nobody
looks at it?

: So fischer - since time dilation and length contraction are velocity
: dependant are you claiming that they too should be abandoned?
: Pmb

I am not claiming anything, instead of trying
to create more things to disagree about you should
get married and have the same things to argue about
as everyone else.

Joe Fischer

--
3

Joe Fischer wrote

You don't know that, and it is certain that
at least one of them has a different opinion of
relativistic mass than you.

First - I seriously doubt that they took something a student told them
and used it for themselves without crediting the student and this is
the only place I know where the term is used. However I may have a
definite answer later.

And I know as a fact that both authors disagree with me with regards
to relativistic mass. I never said they agreed with me at any time.
And in fact I've gone out of my way to say so.

Your problem is double, you see nothing wrong
with using the term relativistic mass, ..

Your problem is that you think there is something wrong with
relativistic mass.

those authors or both called abominable,

So what. Those are two authors out of thousands. Everyone has their
own opinion on this and you're biased on this point to the extreme. So
much in fact that you're completely blind to every other physicist who
disagree with Taylor and Wheeler. For example: Rindler, Mould, Sandin,
D'Inverno etc etc etc

plus
you are unable to see the necessity of all physicists
using the same word to mean invariant rest mass and
a distinctive other word to mean coordinate dependent
energy.

You think there's a problem when none exists. What you want to do is
to force everyone to have the same opinion - that's bull**** - that's
a horrible thing to want to do. Every physicist thinks differently
than every other physicist. And you can't get them all to have the
same opinion. And there's no way that you can force them all to use
the terms that you want. But this has never been a problem in the
physics community because the context almost always tells what the
person means. And in every single instance that I've come across, each
auhor has always explicitly stated what he means.

But if you want to be a pain then fine - for now on the term "mass"
will refer to inertial mass which is the ratio of the magntiude of
momentum and speed. After all that's the way it's always been for the
most part


: You've never really understood the velocity dependance of mass.

Look, mass is measured in it's own rest frame
with precision, bu comparing to a known standard, in
a vacuum chamber.

As I've said - You never really understood the velocity dependance of
mass.


Mass unqualified must mean quantity of matter,..

You claim to adhere to Taylor and Wheeler's ideas and yet you reject
their position on "quantity of matter"?

Nope - that's not what mass refers to.

: The length of a rod varies with speed. The
: rate at which a clock ticks varies with speed -

Compared to what? I have come to think
that you ask questions just to find out the opinion
of others so you can argue the opposite.

See what I mean? You don't understand the meaning of velocity
dependant quantitities

The study of relativity is precisely for the
opposite purpose than the way you use it, it is to
establish a method that will allow all observers
to agree, and obviously you are using it solely
to disagree.

Another clear indication that you don't understand relativity.

: If you see an author
: state in a text "A rod with rest lenght L is moving at 0.9 c. Find the
: length of the rod." then the meaning is obvious. The speed is relative
: to the observer - and the reader is always to take the position of the
: observer in such cases.

So is the rod the same length as the observer finds,
and why would a man say that physics is the same everywhere
and then say that the length of the rod depends on who is
looking at it.

If the rod is oriented parallel to the relative direction of motion
then the moving rod will always be shorted than the same rod when it's
at rest.

You've made a serious error in thinking that because the laws of
physics is the same in all frames that physical quantities must always
be the same in all frames - You don't seem to have read "Spacetime
Phyiscs - 2nd Ed." If you had then you'd never have maked a comment
like this.


Why would a physicist care what an observer sees,

Not sees = measures. And the job of physics is to explain and predict
what is observed in nature.

a physicist should be only interested in the intrinsic
length of the rod.

Very incorrect indeed.
: That is why saying mass increases with velocity
: is stupid, and called abominable by one author.
:
: By THAT author. Not all authors.

And by everybody else who knows anything about
relativity physics.

Very wrong once again.

I see you're not willing to state or demonstrate that you understand
time dilation and Lorentz contraction.

Why is that?

Pmb

Joe Fischer wrote in message ...
Gauge wrote:
: Joe Fischer wrote
: I will comment that the second edition, if that
: was what page 248 was from uses the made up word
: "momenergy", which is moronic.

Other physicists use that term by the way. For example:
http://www.pha.jhu.edu/~neufeld/Phy201/relativity.pdf

which correctly uses the symbol "m" to mean relativistic mass and not
rest mass.

The point is that just as space and time are part of "spacetime" so
too are momentum and energy part of one thing - momenergy.

Pmb

Motion creates inertia of particles. Inertia is the same as
gravity.Particle density means greater gravity. If a particle reached
the speed (motion) of light it gravity would be greater than the gravity
of all the universe Einstien told us that. Bert