What does it mean to set KEd's vi to zero?

[Capiert]

This (thread) is (about)
 a (syntax(_bias)) complaint.
There are several kinds of KE;
 but only 1 is acknowledged.

What does it mean
 to set
 the Kinetic_Energy(_difference)'s
 (KE_d=m*(v_f²-v_i²)/2)

 initial_speed v_i=0
 to zero?

 KE_d=m*(v_f²-0)/2. (?)

 (I mean..)
 If the Kinetic_Energy(_difference)
 KE_d=(m*v_f²/2)-(m*v_i²/2)

 is the 1^st term, the final_kinetic_energy
 KE_f=m*v_f²/2

 minus the 2^nd term, the initial_kinetic_energy
 KE_i=m*v_i²/2

 as,
 KE_d=KE_f-KE_i

 & the initial_kinetic_energy
 KE_i=m*0²/2=0
 is (assumed) zero,
 then we can only have
 the final_Kinetic_Energy
 KE_f=KE_i+KE_d

 KE_f=0+KE_d

 or (when swapping, the sequence order)
 KE_f=KE_d+0

 which "might" appear
 as (the_same=)
 identical
 (when it is NOT always (identical)
 e.g.
 when initial_speed v_i#0
 & initial_kinetic_Energy KE_i#0
 are NOT zero).

Thus (we or)
 I must ask
 (what they ((term_names) really) are (representing)) e.g.
 what is the final_Kinetic_Energy KE_f?;
 & what is the initial_Kinetic_Energy KE_i?;
 & what is the Kinetic_Energy(_difference) KE_d?

It seems
 (to me, (that))
 physicists
 are (absolutely)
 completely (=100%)
 confident
 that the Kinetic_Energy_"difference" KE_d=KE_f-KE_i
 is NOT "The(e)" (=their) Kinetic_Energy KE_f-0
 because

 (perhaps (the) subscripts are (or were) missing?)

 although both
 are (a kind of)
 (kinetic_)Energy.

(But differentiation,
 is a "difference" method
 (adding the series
 (of differences).)

(Why the restriction
 to only 1 kind of KE
 when there are several (kinds)?)

(E.g. (Oh) "KE"(?), we worship (only) "Thee"! (?) :-)
(But which 1?)

(Kinetic is (=implies) "motion",
 thus KE is motion_energy.)

Why do they (physicists)
 bother splitting hairs**
 (just to be different)?

(**E.g.
Tending to ONLY 1 kind, of=from several.
Preferring ONLY
 the KE_difference,
 (when=)with its initial_speed v_i
 (is) set to zero.) 

(I mean)
 (Because..(it seems to me, that))
 the Kinetic_Energy "difference" KE_d
 is "the" most "general"***
 definition
 of Kinetic_Energy;
 & setting its initial_speed v_i=0
 is (but) "only 1" (specific) example
 (of Kinetic_energies, =motion_energies)
 from many (examples). 

(***
 I'( ha)ve stated that,
 in other threads before;
1.
 Energy is suppose to (be accountable, &) add
  if it can NOT be created,
  NOR destroyed;
2.
 but it does NOT always (add (up)),
3.
 although KE_d is (already) relative.
Now including the subscript d=difference (syntax).)

Thus, how can (you or)
 those physicists
 (possibly) suppose
 that:
 the final_Kinetic_Energy KE_f
 (but) minus the initial_Kinetic_Energy KE_i (by letting v_i=0)
 is (suppose to be)
 "the(e)" ONLY Kinetic_Energy KE? (=KE_d)= KE_f- (KE_i=0)
 ((possible)
 that exists,
 & is correct (only) so)? 

[That seems
 to me
 rather "narrow_minded",
 or misled.

E.g. 1 Person's (restriction_)ERROR,
 & then everybody jumps on the (same) bandwagon
 (without thinking).

E.g. NOT quite knowing
 what you are talking about.
=]

DON'T you think
 that'( i)s a little bit
 narrow_minded?
Or misled?

E.g. NOT (quite) the full story.

Or am I wrong?
 & if so why?, etc.

E.g.
Science confirms itself.
There are many ways
 (to Rome=roam). 

Disclaimer:

That was
 (more, or less)
 my complaint
 about (an) inconsistent syntax (bias)
 in physics.

I DON'T claim
 to be perfect (either),
 & (I (also) have
 to make (syntax) compromises
 (e.g. preferences)
 (in order, for them (compromises))
 to remain recognizable
 (at least a bit).

Physics is a straight jacket,
 as Feynman would say.

For those who DON'T know:
"Straight" actually (is) implying,
 too rigid (e.g. &/"or")
 (for the lunatics).

Take it (=&/"or", leave it) either way you want.

It's crazy.

I hope I'm NOT being too impolite;
 & can drop the wool
 from your (biased) eyes.

(I'm biased too, but differently.)

(This is the time=Period
 of revolution,
 & we (=fat Victor & Co)
 are revolting.-Victor Buno. :-)

Why prefer initial_speed zero?

 Einstein said NO (reference_)frame is preferred;
 but that is NOT true.

There are advantages to some;
 or at least
 that is what you are implying=inferring.

E.g. (A mass m, on Earth, with)
 v_i=0 seems static
 but it is really (moving)
 at the same(=identical) speed
 (as the reference_frame, i.e. wrt Earth).

 (& we know the Earth is rotating, e.g. moving.)

 Thus (initial_)speed v_i
 is "inherent".

 It (=v_i)
 (when zero)
 is invisible
 to the (reference_)frame.
(E.g. Zero is =NOTHING, 0 [m/s]. But) 

I can NOT imagine anything
 that is NOT moving
 (wrt the universe).

& even the universe
 must be moving
 wrt some_thing.

[exchemist]

7 minutes ago, Capiert said:

This (thread) is (about)
 a (syntax(_bias)) complaint.
There are several kinds of KE;
 but only 1 is acknowledged.

What does it mean
 to set
 the Kinetic_Energy(_difference)'s
 (KE_d=m*(v_f²-v_i²)/2)

 initial_speed v_i=0
 to zero?

 KE_d=m*(v_f²-0)/2. (?)

 (I mean..)
 If the Kinetic_Energy(_difference)
 KE_d=(m*v_f²/2)-(m*v_i²/2)

 is the 1^st term, the final_kinetic_energy
 KE_f=m*v_f²/2

 minus the 2^nd term, the initial_kinetic_energy
 KE_i=m*v_i²/2

 as,
 KE_d=KE_f-KE_i

 & the initial_kinetic_energy
 KE_i=m*0²/2=0
 is (assumed) zero,
 then we can only have
 the final_Kinetic_Energy
 KE_f=KE_i+KE_d

 KE_f=0+KE_d

 or (when swapping, the sequence order)
 KE_f=KE_d+0

 which "might" appear
 as (the_same=)
 identical
 (when it is NOT always (identical)
 e.g.
 when initial_speed v_i#0
 & initial_kinetic_Energy KE_i#0
 are NOT zero).

Thus (we or)
 I must ask
 (what they ((term_names) really) are (representing)) e.g.
 what is the final_Kinetic_Energy KE_f?;
 & what is the initial_Kinetic_Energy KE_i?;
 & what is the Kinetic_Energy(_difference) KE_d?

It seems
 (to me, (that))
 physicists
 are (absolutely)
 completely (=100%)
 confident
 that the Kinetic_Energy_"difference" KE_d=KE_f-KE_i
 is NOT "The(e)" (=their) Kinetic_Energy KE_f-0
 because

 (perhaps (the) subscripts are (or were) missing?)

 although both
 are (a kind of)
 (kinetic_)Energy.

(But differentiation,
 is a "difference" method
 (adding the series
 (of differences).)

(Why the restriction
 to only 1 kind of KE
 when there are several (kinds)?)

(E.g. (Oh) "KE"(?), we worship (only) "Thee"! (?)
(But which 1?)

(Kinetic is (=implies) "motion",
 thus KE is motion_energy.)

Why do they (physicists)
 bother splitting hairs**
 (just to be different)?

(**E.g.
Tending to ONLY 1 kind, of=from several.
Preferring ONLY
 the KE_difference,
 (when=)with its initial_speed v_i
 (is) set to zero.) 

(I mean)
 (Because..(it seems to me, that))
 the Kinetic_Energy "difference" KE_d
 is "the" most "general"***
 definition
 of Kinetic_Energy;
 & setting its initial_speed v_i=0
 is (but) "only 1" (specific) example
 (of Kinetic_energies, =motion_energies)
 from many (examples). 

(***
 I'( ha)ve stated that,
 in other threads before;
1.
 Energy is suppose to (be accountable, &) add
  if it can NOT be created,
  NOR destroyed;
2.
 but it does NOT always (add (up)),
3.
 although KE_d is (already) relative.
Now including the subscript d=difference (syntax).)

Thus, how can (you or)
 those physicists
 (possibly) suppose
 that:
 the final_Kinetic_Energy KE_f
 (but) minus the initial_Kinetic_Energy KE_i (by letting v_i=0)
 is (suppose to be)
 "the(e)" ONLY Kinetic_Energy KE? (=KE_d)= KE_f- (KE_i=0)
 ((possible)
 that exists,
 & is correct (only) so)? 

[That seems
 to me
 rather "narrow_minded",
 or misled.

E.g. 1 Person's (restriction_)ERROR,
 & then everybody jumps on the (same) bandwagon
 (without thinking).

E.g. NOT quite knowing
 what you are talking about.
=]

DON'T you think
 that'( i)s a little bit
 narrow_minded?
Or misled?

E.g. NOT (quite) the full story.

Or am I wrong?
 & if so why?, etc.

E.g.
Science confirms itself.
There are many ways
 (to Rome=roam). 

Disclaimer:

That was
 (more, or less)
 my complaint
 about (an) inconsistent syntax (bias)
 in physics.

I DON'T claim
 to be perfect (either),
 & (I (also) have
 to make (syntax) compromises
 (e.g. preferences)
 (in order, for them (compromises))
 to remain recognizable
 (at least a bit).

Physics is a straight jacket,
 as Feynman would say.

For those who DON'T know:
"Straight" actually (is) implying,
 too rigid (e.g. &/"or")
 (for the lunatics).

Take it (=&/"or", leave it) either way you want.

It's crazy.

I hope I'm NOT being too impolite;
 & can drop the wool
 from your (biased) eyes.

(I'm biased too, but differently.)

(This is the time=Period
 of revolution,
 & we (=fat Victor & Co)
 are revolting.-Victor Buno.

Why prefer initial_speed zero?

 Einstein said NO (reference_)frame is preferred;
 but that is NOT true.

There are advantages to some;
 or at least
 that is what you are implying=inferring.

E.g. (A mass m, on Earth, with)
 v_i=0 seems static
 but it is really (moving)
 at the same(=identical) speed
 (as the reference_frame, i.e. wrt Earth).

 (& we know the Earth is rotating, e.g. moving.)

 Thus (initial_)speed v_i
 is "inherent".

 It (=v_i)
 (when zero)
 is invisible
 to the (reference_)frame.
(E.g. Zero is =NOTHING, 0 [m/s]. But) 

I can NOT imagine anything
 that is NOT moving
 (wrt the universe).

& even the universe
 must be moving
 wrt some_thing.

Yes, well, kinetic energy has to be specified with respect to a frame of reference, because velocity is relative. 

Why can't you post in normal length lines? This style is very exhausting to read. It makes one question whether it is worth the trouble.  

[Capiert]

1 hour ago, exchemist said:

Yes, well, kinetic energy has to be specified with respect to a frame of reference, because velocity is relative. 

I find that a good answer.
It implies admitting ~1/2 the problem.

But DON'T you think
 that (reference frame) need
 has been created artificially,
 by negating
 the initial_speed v_i
 to zero?

Now you have
 to suffer the consequences
 & are happy
 with it(s complexity).

1 hour ago, exchemist said:

Why can't you post in normal length lines?

This style
 helps me
 reduce my errors,
 which otherwise would then be "more" confusing
 to you.

It helps me find subtle problems.

1 hour ago, exchemist said:

This style is very exhausting to read.

Sorry, (1st draft, needs maybe a 5th re_edit?)
 that's my handicap.
It's a construct, e.g. programmed.
Intended to read
 with natural pauses
 almost automatically;
 but sometimes
 it has to be broken down more
 (e.g. bracketed, (is (superfluous &) put) to the right end, (thus) ignorable)
 but gets messy.
Me (when) against many
 (must be perfect,
 but isn't).
It takes a lot of backbone
 to go "against" mainstream (errors?).
(Sometimes) It's difficult to (get=) crystalize the ideas
 in order to (quickly?) pinpoint the problems;
 instead of make new 1's.
I write more naturally
 when I feel uninhibited.
Swansont will say there are NO errors
 in physics;
 only me,
 but sorry I DON'T believe him
 on some things (yet).

1 hour ago, exchemist said:

It makes one question whether it is worth the trouble.  

It's pointing at a serious problem.
Prejudice (bias), & ignorance of it.

Please DON'T bother.
It's intended to hedge (=prevent)
 future problems (conflicts).

It'( ha)s obviously failed
 for now.

I DON'T like it either.
Stressy bad weather.

Edited January 15, 2023 by Capiert

[swansont]

4 hours ago, Capiert said:

This (thread) is (about)
 a (syntax(_bias)) complaint.
There are several kinds of KE;
 but only 1 is acknowledged.

What other “kinds” of KE are there? I only know of the “kind” that is given by 1/2 mv^2

It can be applied to different particles and be measured/calculated at different times (hence you have initial and final as two common times)

3 hours ago, Capiert said:

But DON'T you think
 that (reference frame) need
 has been created artificially,
 by negating
 the initial_speed v_i
 to zero?

Reference frames are incredibly useful for those that actually solve physics problems.

 

4 hours ago, Capiert said:

the Kinetic_Energy "difference" KE_d
 is "the" most "general"***
 definition
 of Kinetic_Energy;

No. the difference in kinetic energy represents the change in kinetic energy at two different points in time. It is not a definition of KE. 

[exchemist]

3 hours ago, Capiert said:

I find that a good answer.
It implies admitting ~1/2 the problem.

But DON'T you think
 that (reference frame) need
 has been created artificially,
 by negating
 the initial_speed v_i
 to zero?

Now you have
 to suffer the consequences
 & are happy
 with it(s complexity).

This style
 helps me
 reduce my errors,
 which otherwise would then be "more" confusing
 to you.

It helps me find subtle problems.

Sorry, (1st draft, needs maybe a 5th re_edit?)
 that's my handicap.
It's a construct, e.g. programmed.
Intended to read
 with natural pauses
 almost automatically;
 but sometimes
 it has to be broken down more
 (e.g. bracketed, (is (superfluous &) put) to the right end, (thus) ignorable)
 but gets messy.
Me (when) against many
 (must be perfect,
 but isn't).
It takes a lot of backbone
 to go "against" mainstream (errors?).
(Sometimes) It's difficult to (get=) crystalize the ideas
 in order to (quickly?) pinpoint the problems;
 instead of make new 1's.
I write more naturally
 when I feel uninhibited.
Swansont will say there are NO errors
 in physics;
 only me,
 but sorry I DON'T believe him
 on some things (yet).

It's pointing at a serious problem.
Prejudice (bias), & ignorance of it.

Please DON'T bother.
It's intended to hedge (=prevent)
 future problems (conflicts).

It'( ha)s obviously failed
 for now.

I DON'T like it either.
Stressy bad weather.

Sorry, I really can't be bothered to wade through all this, er, stuff. Format it properly or I'm out. 

[Endy0816]

Saying some mass went from 0mph to 60mph is just simpler than saying it went from 30mph to 90mph.

Velocity value is basically arbitrary, as long as you are consistent about things.

If I'm measuring my velocity as zero relative to myself, I can't tell the cop that pulled me over for speeding that I'm also going zero relative to the road. That doesn't work.

 

[swansont]

5 minutes ago, Endy0816 said:

Saying some mass went from 0mph to 60mph is just simpler than saying it went from 30mph to 90mph.

In most cases. 

But the underlying principle is that you will get the same physics result, regardless of your choice of frame of reference.

[Mordred]

1 hour ago, exchemist said:

Sorry, I really can't be bothered to wade through all this, er, stuff. Format it properly or I'm out. 

I agree @Capiertthere is absolutely no reason to have a few words on each line it makes your posts look like bad poetry please fill in the lines so everyone can actually follow what you are posting

[Lorentz Jr]

6 hours ago, Capiert said:

What does it mean to set the Kinetic_Energy's (KE_d=m*(v_f²-v_i²)/2) initial_speed v_i=0 to zero?

 KE_d=m*(v_f²-0)/2. (?)

It means you're analyzing the problem in the object's initial reference frame.

It may simplify the math a bit.

6 hours ago, Capiert said:

  what is the final_Kinetic_Energy KE_f?;

It's the object's kinetic energy at the end of the experiment.

6 hours ago, Capiert said:

 & what is the initial_Kinetic_Energy KE_i?;

It's the object's kinetic energy at the beginning of the experiment.

It may be zero, but it doesn't have to be.

6 hours ago, Capiert said:

what is the Kinetic_Energy(_difference) KEd?

It's the difference between the final and the initial.

Edited January 15, 2023 by Lorentz Jr

[Capiert]

On 1/15/2023 at 9:41 PM, swansont said:

What other “kinds” of KE are there?

KEf=KEi+KEd
That looks like 2 others to me.
Yours is
 KEd=KEf-KEi,
 you let KEi=0.

On 1/15/2023 at 9:41 PM, swansont said:

I only know of the “kind” that is given by 1/2 mv^2

It can be applied to different particles and be measured/calculated at different times (hence you have initial and final as two common times)

That's a good (interesting, simple) perspective.

But what about KE transfer
 between (accelerating) masses
 that have acquired KE in similar times?

Or is that what you mean (already)?

I will assume
 the syntax
 could get
 a bit hairy.

On 1/15/2023 at 9:41 PM, swansont said:

Reference frames are incredibly useful for those that actually solve physics problems.

On 1/15/2023 at 9:41 PM, swansont said:

No. the difference in kinetic energy represents the change in kinetic energy at two different points in time. It is not a definition of KE. 

In other words
 you are saying,
 KE applies
 to only 1 accelerated mass.

On 1/16/2023 at 12:17 AM, Lorentz Jr said:

It means you're analyzing the problem in the object's initial reference frame.

It may simplify the math a bit.

It's the object's kinetic energy at the end of the experiment.

It's the object's kinetic energy at the beginning of the experiment.

It may be zero, but it doesn't have to be.

How do we know (if) the initial_kinetic_energy KEi is zero or NOT?

It (=KE) is always wrt the initial_speed
 of the reference_frame;
 but does that say or mean zero KE?

If the reference frame is moving
 (which it surely is)
 then we can NOT say a static mass
 wrt to that reference_frame
 has absolutely NO KE.

On 1/16/2023 at 12:17 AM, Lorentz Jr said:

It's the difference between the final and the initial.

 

Edited January 20, 2023 by Capiert

[swansont]

23 minutes ago, Capiert said:

KEf=KEi+KEd
That looks like 2 others to me.
Yours is
 KEd=KEf-KEi,
 you let KEi=0.

Those are not “kinds” of KE.

KE_i and KE_f are the kinetic energy at two points in time.

 

23 minutes ago, Capiert said:

That's a good (interesting, simple) perspective.

But what about KE transfer
 between (accelerating) masses
 that have acquired KE in similar times?

 

What about it?

There are several equations one might use to determine the KE, depending on the details of the problem.

But there will still be a KE at the beginning if the problem, and one at the end.

 

23 minutes ago, Capiert said:

In other words
 you are saying,
 KE applies
 to only 1 accelerated mass.

No, I didn’t mean that, nor did I say that. Every object can have a value for KE. 

 

23 minutes ago, Capiert said:

How do we know (if) the initial_kinetic_energy KEi is zero or NOT?

If the object is at rest, it has zero KE. v=0, and KE = 1/2 mv^2