Re: "Where Is The Kinetic Energy of a Bullet Stored?"


jgreenfield@xxxxxxxxxxx wrote:
> PD wrote:
> > jgreenfield@xxxxxxxxxxx wrote:
> > >
> > > Yeh???????? What happened to .088 ?????????
> > > Hint: The FoR is ONE system, containing the plane, the bomb, and the
> > > impact point.
> > > Your calculations are done merely from different perspective WITHIN
> > > that FoR.
> > > A real FoR "difference" (observer uninvolved with the system, say in
> > > another plane), could arrive at differring results, if he was not smart
> > > enough to rectify the illusions caused by geometry (and to a lesser
> > > extent, the c'=c+v factor dictating information transfer)
> >
> > Ahh, at last we get down to the problem. You do not understand the term
> > frame of reference as used by physicists. In fact, you have a
> > misconception that is similar to TomGee's. However, he thinks that a
> > frame of reference must have a physical object at the origin, and so if
> > two objects collides, he think this is the only moment where two frames
> > of reference coincide. Your mistake is somewhat different, but you
> > still do not understand the term FoR. As long as we are not operating
> > with the same definitions for terms, we can't discuss anything.
>
> Tom Gee (may) agree with me, in that dealing in coordinates only (and
> thereby ignoring mass/energy/momentum), the math of SR support is
> magical imagination ONLY. It does not apply to reality, where such
> cannot be ignored.

Two comments:
1. You'll note my example does not invoke SR in any way, shape or form.
It is an example of Galilean relativity, as taught in chapter 2 of most
introductory physics textbooks. Thus your complaint appears to be not
with Einstein, but with Galileo and Newton and every chapter but the
first one in any introductory physics textbook. I can't tell yet
whether you have a problem with the first chapter, as well.
2. My complaint with TomGee is the same as the one I have with you,
that he uses physics terms with the implication that he knows what they
mean, but he's not read anything that would give him an understanding
of what they mean. He does feel it's necessary to read anything in
order to have a proper understanding, even when it's pointed out that
he is misusing the term.

> >
> > > >
> > > > The thing to note is that it's the *law* (that says that energy is
> > > > conserved) that holds true regardless of the choice of reference frame.
> > > > You'll also notice however, that *values* for the total energies (and
> > > > in fact, of the kinetic and potential energies) are different between
> > > > the two reference frames. It's also worth noting that nowhere did I
> > > > bring in SR for this analysis; and indeed the velocities are low enough
> > > > that the numbers would not have been different had I included it.
> > >
> > > Those values could be set in concrete, _IF_ we could determine absolute
> > > rest (universal).
> >
> > Agree, but we can't. There is no evidence anywhere of a universal
> > frame.
>
> Why not use the origin of the Big bang?
> (not that there was one)

Exactly. Not that there was one.

> >
> > > Meanwhile, we are subject to illusion (read guess the real universal
> > > values)
> >
> > No. The point is the *values* themselves are immaterial. The *laws* are
> > what count. And you'll note that the laws, as exemplified in my
> > example, are immutable even if the values are not.
>
> "We hereby decree that this amount of fuel will produce x result when
> used in frame A: we further pass a law that said fuel will do y in
> frame B"

And what is the physical law at work there? While you think about how
to say that carefully, consider my flight this morning which flies from
east to west and when I arrive it will be one hour later than when I
took off. Yet a few days ago, when I flew the same route from west to
east, and spent the same time in the air, I landed three hours later
than when I took off. In this scenario, I'm using the line between the
earth and the sun as an axis in my chosen reference frame.

> >
> > > >
> > > > You'll also note that I didn't *do anything physical* to the bomb in
> > > > switching from one reference frame to another. I only made the
> > > > measurements of height and speed in a different coordinate system. So I
> > > > didn't have to somehow *add* an energy of 2.5E5 J to the bomb to look
> > > > at it from a different reference frame, though in fact the difference
> > > > in the total energies as measured in these frames is precisely that.
> > > > There was nothing physically different happening to the bomb in the two
> > > > cases; in both cases, the bomb was released and gravity accelerated the
> > > > bomb. Since there was nothing physically different in the two cases,
> > > > there was no agent that could "stick in" another 2.5E5 J of energy.
> > > > This should give you a glimmer that this energy is not "stored" in the
> > > > bomb somehow.
> > >
> > > Why did the pilot allow for EXTRA FUEL in order to take the bomb to
> > > (joke) zero altitude?
> > > If the fuel energy is NOT in the bomb, WHERE IS IT?
> >
> > That's the point. Energy is not "stuff" that sits inside objects.
> > Energy is a property of a system. It cannot be reliably partitioned
> > among the objects in a system.
>
> "Reliably"????? Is that SR speak for "*** knows what happens to it"?
> BTW: you just attacked Tom Gee for requiring "objects in a system".
> Make up your mind!

I'm not requiring objects in the system either, nor am I insisting that
the origin of the reference frame be tied to one of the objects (if
any) in the system. I'm explicitly stating that the enegy does not "sit
in" any object in the system, and so I'm not requiring objects in a
system. And this doesn't have anything to do with SR, as I've pointed
out repeatedly to you.

> >
> > > >
> > > >
> > > > > IF that is the case, as velocities DON'T add algebraically under SR
> > > > > rules of velocity addition, then energy MUST be NOT conserved.
> > > >
> > > > Sorry, that simply does not follow.
>
> one photon has x energy; another x energy........BUT SR says the two
> do NOT have 2x energy

It does?

> (because c + c < 2c

That's adding velocities, not energies. Explain (explicitly) why one
implies the other.

> So it follows OK. You just can't see the contradictions (read
> impossible contradictions-- UNLESS energy is not conserved)
> > > >
> > > > > (when adding the "slopes" of speed, the energy required to provide the
> > > > > change of direction in the geometry is ignored.)
> > > >
> > > > I have no idea what you're talking about here.
>
> Surely you learned this at the AE tit? SR MUST use this bull*** method
> of adding velocities.

I'm sorry... reference, please? I can add velocities properly without
adding any "slopes". Where are you getting the impression that it does?
What passage of what reading has caused you this great confusion?

> > >
> > > Go to the library------> "adding velocities in SR" ----------> look
> > > at the "slopes" and realise that if these represent real object's
> > > velocities, then their trajectories have been ALTERRED
> >
> > Nope. Not so. Perhaps you should give me a concrete example, as I gave
> > one for you.
>
> What? The direction of the bullet is NOT different to that of the (gun
> fired when moving), under SR addition rules?

Certainly not necessarily.
On the other hand, putting SR aside, if I swim across a river and I
intentionally only stroke so that I'm always pointed northward, my
direction will not be northward to someone standing on the shore. But
that's true even of Galilean relativity, where the rule for velocity
combination IS presumed to be a simple sum.

>
> (place affidavit to that effect here)

See above.

>
> Jim G
> c'=c+v

.

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