That'( i)s how you (would) do it.
E.g. Just so you do NOT have to bother.
But why should I (try to) believe you.
You have given me NO proof,
with your inability
NOT to bother (attitude).
Are all scientists so lazy
(like Minkowski hinted
about Physicists)?
(Surely NOT!)
Why should (some of the kinetic) energy leave that system?
(& I DON'T accept warm, acoustic, excuses either.)
(I'd like to see (simple) tangible measurements.)
Oh! Abracadabra (then).
(It's a mystery!)
That sounds like a boring disinterest in science
e.g. trying to know.
A half hearted attempt
to throw a few things together.
You either: know; or (else) you DON'T,
& you obviously DON'T,
because you give me useless excuses.
Sorry, other people can try to be more thorough.
You DON'T even give the effort.
If you (were to) say:
those answers can NOT be found;
then there must be a reason why.
(Oh we are too feeble,
(at) attempting, (to) zero_speed, =zero results.
It's more difficult that c.)
Disinterest is NO excuse.
You also avoid commenting
(up)on the (=my)
initial_kinetic_energy KEi
(perhaps because you habitually evade it
by subtracting it away).
My syntax includes KEi.
(What is your syntax,
if mine is NOT an extended (syntax)?)
All 3 (named KEs)
KEf=KEi+KEd
are "kinetic_energies"
((meaning) NOT your "the"(what? _unknown),
NOT mentioned f form) syntax).
You can clearly see that
(they are kinetic_energies)
in my syntax "KE"
with a subscript.
There is NO difference:
meaning a KE is a KE,
whatever its subscript is.
The KEd can (equally)
accelerate a(ny) mass
from zero (speed)
to a (new) final_speed vf,
which would finally have
its own KEf(new)=KEd
equal to that kinetic_energy_difference KEd.
I DON'T see why you try
to sell a KEd distinction
(away) from any other KEsubscripted
just because you do NOT know
what (else) KEd is
(or could be).
E.g.
Even though you only want KEf
to be "the" (only) kind of KE (possible).
It is absurd to say: KEd
is NOT a kinetic_energy
simply because it is NOT "the" final_KE
KEf=m*(vf2-0)/2
which uses the mass m multiplied
by half the final_speed squared vf2
but "subtracted by zero(_squared)"!
The initial_kinetic_energy
KEi=m*(vi2-0)/2
is also a kinetic_energy
(just like KEf is)
because its
half the initial_speed squared vi2
but is also "subtracted by zero(_squared)"!
The universal
KE_difference formula
KEd=m*(vf2-vi2)/2
is the most universal
KE "definition"!
There you can (=may)
use any reference(_frame) speed
vref=vi
(below c, that)
you want
to be your reference speed
(e.g. at rest, when identical
to the initial_speed vi).
If I have 7 oranges (analogy KEf)
& subtract 4 (oranges, analogy KEi),
then I would expect out, 3 (oranges, analogy KEd)
like any reasonable thinking person.
NOT grapefruits or "lemons"! (or other hogwash).
That's only common sense,
which seems to be missing here
(in (what some people call) science).
You DON'T (even) have a clue where the energy has gone,
you DON'T know what it is (e.g. called, other than "difference")
& yet want to be called scientists.
(& you want me to believe you?)
Modern physics is like modern art,
anything goes,
even junk.
All that matters is who (e.g. what ego) has the say.
I suspect you mean,
the initial_speed terms
(e.g. KEi)
are subtracted anyway;
(&) so why bother.
?
Taken from a different perspective,
of: if the 2 masses are on Earth
& the Earth is rotating
let'( u)s say vi=~1 [km/s]
eastwards
((just) to keep things simple,
at where they are
on the Earth's surface);
then they are still moving
~1 [km/s]
although they appear
to you
as at rest.
(& that KEd did NOT leave the system.)
What seems (as) "at rest"
is an optical delusion
(of) for both: observer;
& an object,
having the same (=identical) speed.
(E.g. Even though they are separated
by a distance d.)
In reality (e.g. the universe),
(we know)
everything is moving.
Meaning NOTHING is (really) static (=at rest, with zero speed).
(Everything has a speed difference
wrt some other (moving) object (reference, frame).)
Your "choice"
of reference(_frame)
(e.g. of same speed
as the observed object)
(help) determines
whether you want
to be: deceived ((in)to think(ing): )
an object is at rest (when it has the same speed
as the reference_frame);
or NOT!
**(Sorry! (Yes) "I") Modified.
(Or do you mean your quote is dishonest? Which I (rather) doubt,
in preference for the former.)
How else should I add (extra) comments
of mine
into your text?
I bracketed it,
to distinguish it from your original text.
Dishonesty was NOT intended;
only clearness of the discussion
(was intended),
(before getting lost again
in(to) confusion
between syntaxes).
Should I use different brackets?