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femr2 · 28th June 2012, 06:29 AM

Originally Posted by pgimeno

Approximately constant distance (or with a negligible percent in variation, as in the case of the Dan Rather viewpoint) results in negligible need for correction.

Agreed. The correction is of lower magnitude than the error resulting from defining building scaling metric on the Dan Rather footage, so it's a bit pointless.

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With that 3D info it would then be possible to perform full perspective correction.

I could use SynthEyes to resolve the 3D motion using multiple "shots", but the problem with that (automated route AND manual as you're describing) is the significant increase in noise.

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I'm interested in the shape of the curve for the first moments.

Not a problem.

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There's little N-S movement at that point. I haven't compared the height of the windows near the bottom with that near the top; that can also give an idea of the influence of perspective.

It's fairly small, but not negligible.

pgimeno · 28th June 2012, 06:45 AM

Originally Posted by femr2

I could use SynthEyes to resolve the 3D motion using multiple "shots", but the problem with that (automated route AND manual as you're describing) is the significant increase in noise.

The aim I had in mind is not to use a 3D trace for graphing, only for estimating distance to the camera over time for perspective correction. I expect that a heavily smoothed version of the 3D trace would suffice for that purpose. Microscale movements have negligible influence in the perspective correction. It would just be an additional refinement to the vertical position data.

Originally Posted by femr2

[Influence of perspective is] fairly small, but not negligible.

Mostly agreed. That's why I've suggested using the camera position for the correction; the distance between the windows can serve as a secondary check, and also to have an initial idea before going into the more complex calculations.

Christopher7 · 28th June 2012, 11:51 AM

Originally Posted by femr2

Use your words. A YT link does not answer your assertions about NIST and Chandler.

Chandler explains what he did and what the software did. You ask for things you know don't exist and do not need to be known in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'.

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Then you'll have no issue adding a ~ prefix to your "FFA" every time you state it then.

Only deniers would do that. Chandler said "indistinguishable from free fall acceleration" and NIST said "at free fall"

NIST measured to within 1/10th of 1%. The difference is negligible - to small to be considered. As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100' and claiming that NIST and Chandler don't know what they are talking about I will continue to post these facts.

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A while since I've been called a "denier". Denying what ?
No-one is denying a period of ~FFA.

It's the ~ that's important there.

Double talk. Your implication in using ~ is that it is not FFA, correct? You can't have it both ways.

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What caused early motion of the building, as-in...the building was in motion long before it started to drop. What caused that motion ?

Irrelevant to the period of FFA.

Originally Posted by C7

Draw the line that shows your interpretation.
http://img515.imageshack.us/img515/2535/femr5e.jpg

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Sure...
http://femr2.ucoz.com/_ph/7/2/447669743.jpg

On the velocity graph.

I just moved the line up to show how it fits the data before the moment of >g [which is probably a slight movement in the camera several miles away].

.

femr2 · 28th June 2012, 12:21 PM

Originally Posted by Christopher7

Chandler explains what he did and what the software did.

Yet you are unable to type them. Big surprise.

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You ask for things you know don't exist

Incorrect. I've told you the answers several times within this very thread. It seems you're simply too dense to even notice.

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and do not need to be known

When you repeatedly say stupid things like...

Originally Posted by Christopher7

The programs NIST and Chandler used were designed to calculate acceleration.

...whilst freely admitting, when asked what "programs" they use. that...

Originally Posted by Christopher7

[you] don't know.

That's just dumb.

Again, I've TOLD you numerous times...

Originally Posted by femr2

You don't know what "programs" were used, because you simply don't understand. I've told you what I use:

a) SynthEyes - Professional feature tracking system, which I use to extract motion data from video with high precision. I've used many similar systems and SynthEyes has by far the most accurate tracking engine.

b) OriginPro - Professional data analysis and math environment, which I use to perform Savitzky-Golay smoothed derivation of raw data.

c) Excel - Which I use to translate from pixel units to real-world units, and generate the many lovely graphs I post.

Now then...

NIST placed "dots" on video by hand. So did Chandler. Awful.
Chandler may have redone his trace with Tracker, but likely did not use it's primitive tracking facilities.

NIST derived data using simple central difference approximation, probably with Excel or Matlab, though a piece of paper would do. Chandler's freebies "Physics Toolkit/Tracker" performed a similar symmetric difference derivation.

Yet you STILL don't know. Yet you still keep saying the "programs" they used "were designed to measure velocity and acceleration". Bizarre.

So, comprehension test...have a go at answering my questions again.

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in an attempt to claim that NIST and Chandler don't know what they are talking about

As I already said to you, YOU don't even understand what they ARE saying. I've repeatedly told you that it's not about them not knowing what they are talking about, simply that their analyses use low fidelity data, and their results are inaccurate. What part of that do you not understand ?

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when they said WTC 7 fell at free fall for ~100'.

Firstly, NIST don't say that. With local context...

...NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period.

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Only deniers would do that.

lol.

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Chandler said "indistinguishable from free fall acceleration"

~FFA.

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and NIST said "at free fall"

Nah...

NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period.

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As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100'

What is wrong with you ?

No-one is denying ~FFA for a period of time, indeed I am ADDING a period >FFA.

What part of that are you having a problem with ?

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and claiming that NIST and Chandler don't know what they are talking about

Where do I claim such ? I highlight problems with their data and studies, absolutely, as those issues are all real.

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I will continue to post these facts.

You're not posting "facts". You're posting "crap". You know you're posting crap. Transparent. Obvious.

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Double talk. Your implication in using ~ is that it is not FFA, correct?

Jebus. What does "~" mean ?

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You can't have it both ways.

lol.

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Irrelevant to the period of FFA.

~FFA. ffs.

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On the velocity graph

The line indicating ~FFA is already on the graph son.

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I just moved the line up to show how it fits the data

It doesn't fit. You don't know what you're doing. Stop it.

DGM · 28th June 2012, 01:01 PM

Originally Posted by Christopher7

and NIST said "at free fall"

.

No, they didn't. Wouldn't that make you a fraud?

Let me guess, you subscribe to the belief it's OK to "lie for truth".

Christopher7 · 28th June 2012, 02:40 PM

Originally Posted by femr2

Firstly, NIST don't say that. With local context...

...NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period.

You hang you hat on the qualifiers and ignore the scientific conclusion.
"the north face descended at gravitational acceleration"

~~~FFA.~~ FFA
The difference is so tiny that it is not worth considering. Only a devout denier would try to imply that it is not FFA.

Originally Posted by C7

claiming that NIST and Chandler don't know what they are talking about

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Where do I claim such ? I highlight problems with their data and studies, absolutely, as those issues are all real.

You just did.

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What does "~" mean ?

That was the question. When you use ~ does that mean that it was NOT FFA?

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The line indicating ~FFA is already on the graph.

Non answer. You say there is .5s of >g. Where? draw lines to indicate where it is.

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It doesn't fit.

Yes it does. It fits as well as the 1.8s of g. The data points are not perfect because they are taken from a video. You have acknowledged that.

In any case, the first 0.7s are at or greater than FFA. i.e. NO RESISTANCE!

GlennB · 28th June 2012, 02:47 PM

And C7 will argue forever and a day about sub-pixel levels of accuracy in video analysis while blithely ignoring the absence of the 000's of explosions required to support his weird theory.

"Straining at gnats" is a good expression, and sums him up well.

DGM · 28th June 2012, 03:21 PM

Originally Posted by GlennB

And C7 will argue forever and a day about sub-pixel levels of accuracy in video analysis while blithely ignoring the absence of the 000's of explosions required to support his weird theory.

"Straining at gnats" is a good expression, and sums him up well.

You would almost expect Chris7 to post page after page of traces of buildings destroyed by controlled demolition falling at "free fall", but, he does not.

Why is this Chris7? This is a "classic sign" of controlled demolition, right?

femr2 · 28th June 2012, 04:50 PM

Originally Posted by Christopher7

You hang you hat on the qualifiers and ignore the scientific conclusion.

Incorrect.

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~~~FFA.~~

Incorrect.

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The difference is so tiny that it is not worth considering.

Incorrect.

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Only a devout denier would try to imply that it is not FFA.

Incorrect.

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You just did.

Incorrect.

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That was the question. When you use ~ does that mean that it was NOT FFA?

Really ?

"~" = "approximately".

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Non answer.

Incorrect.

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You say there is .5s of >g

Incorrect. ~0.5s.

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Where? draw lines to indicate where it is.

No need. Use the acceleration graph. Anything below ~-32.2ft/s² is >g.

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Yes it does.

Incorrect.

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It fits as well as the 1.8s of g.

Incorrect.

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The data points are not perfect because they are taken from a video.

Partially correct.

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You have acknowledged that.

Correct !

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In any case, the first 0.7s are at or greater than FFA

Incorrect.

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i.e. NO RESISTANCE!

Incorrect.

11 Incorrect.
1 Correct.
3 Middlin'

You do not win a prize.

Try harder next time.

Christopher7 · 28th June 2012, 10:37 PM

Originally Posted by C7

That was the question. When you use ~ does that mean that it was NOT FFA?

Originally Posted by femr2

Really ?

"~" = "approximately".

Non answer. When you use ~/approximately do you mean it was not FFA ?

Originally Posted by C7

Where? draw lines to indicate where it is.

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No need. Use the acceleration graph. Anything below ~-32.2ft/s² is >g.

Cop-out. I have shown that your velocity graph shows:
ETC: FFA for ~0.4s, then >g for ~0.3s. then FFA for 1.8s.

You cannot refute this so you refuse to answer directly. We could quibble about 0.2s of >g but that's not the point.

Your velocity graph shows FFA or greater. There is NO <g until 14.9s - 85'.

Just saying incorrect without saying why is worthless.

Oystein · 29th June 2012, 02:35 AM

Originally Posted by Christopher7

...
No, the data points [dots] are inaccurate due to the fact they are taken from a video. Some are more inaccurate than others. That's why the program has a feature that computes the average and draws the line.
...

C7, do you have Chandler's data points in tabulated form? As a list of pairs of numerical values "time|drop distance"? This as opposed to "dots" or "lines" drawn in a chart.

Thanks

femr2 · 29th June 2012, 04:36 AM

Originally Posted by Christopher7

Non answer.

Incorrect.

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When you use ~/approximately do you mean it was not FFA ?

The inclusion of the approximate qualifier is non-optional, and means just that...approximate. You, as you are clearly a bit dim, might want to think of some other words, like equivalent, estimation, average...things like that.

Stick a ~ in front of "FFA" when you write it, and I'll give you a lot less grief. Oh, but make sure you don't state ridiculous incorrect ~FFA periods suggesting my data supports your nonsense, as it doesn't. Being very generous you could say my data suggests ~1.75s of ~FFA. More than that and I'll be on your case.

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I have shown that your velocity graph shows

You really haven't.

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You cannot refute this so you refuse to answer directly.

ROFL. My graph shows there are Klingons on the starboard bow. You cannot refute this so you must now sit in the corner wearing the blue dunce hat. Refute what ? You pulling faeces out of thin air ? I've tried to tell you many times. The time to simply point and laugh instead is approaching rapidly I'm afraid.

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We could quibble about 0.2s of >g but that's not the point.

No, the point is that your severe lack of understanding, in combination with your willful refusal to learn from (or even admit) (or, ffs, even recognise) your mistakes, in conjunction to your blind desire to see what you want to see...renders your dialogue totally pointless, repetative and really, really boring.

Without your problems above, you could have simply improved your understanding a long time ago, and be discussing the correct details, rather than waste my time going round in circles with the REALLY simplest of friggin things imaginable.

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Just saying incorrect without saying why is worthless.

Saves me time. It's not like you're ever going to learn anything. You just don't want to.

femr2 · 29th June 2012, 05:49 PM

Originally Posted by Christopher7

in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'.

Here's Chandler's "re-done" WTC7 velocity plot...

In your own words, please explain how the **** you get from that remarkably non-linear (aka wiggly) line, which, of course you understand cannot imply a constant acceleration, "FFA" or not, to saying "indistinguishable from freefall" ?

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Chandler said "indistinguishable from free fall acceleration"

Correct. He really shouldn't have, should he.

Christopher7 · 30th June 2012, 01:36 AM

Originally Posted by femr2

Here's Chandler's "re-done" WTC7 velocity plot...

http://femr2.ucoz.com/_ph/7/117268871.png

In your own words, please explain how the **** you get from that remarkably non-linear (aka wiggly) line, which, of course you understand cannot imply a constant acceleration, "FFA" or not, to saying "indistinguishable from freefall" ?

The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration.

This is basic high school physics that most high school aged people can understand.

ozeco41 · 30th June 2012, 01:40 AM

Originally Posted by Christopher7

The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration.

This is basic high school physics that most high school aged people can understand.

Chandler versus femr2 ???

My money is on femr2.

...even us older folk understand physics. But we weren't "taught" by Chandler.

femr2 · 30th June 2012, 04:14 AM

Originally Posted by Christopher7

The wiggly line assumes that the data points are accurate.

The "wiggly line" is not sentient, and assumes nothing.

The line simply connects the actual data-points.

The RESULT is a "wiggly line".

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Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video.

There is certainly an amount of error introduced by extracting the data from video, however, you do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one.

All you achieve is an average, an estimation, an approximate result that is easier to "read".

The question you must ask, is how you KNOW that variation is "noise" and not "real" ?

The answer, as I know you'll fluff it, is that you don't know.

There are ways of "cutting through noise", but a linear fit is FAR from the best or most accurate way to do that.

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The deviation from free fall line is that inaccuracy, not a variation in the acceleration.

Utterly, obviously, simply incorrect...in this case, as we DO have more accurate data available, mine.

My data shows that some of that variation is indeed "real".

My acceleration profile is much closer to actual, and reveals detail not presented by either Chandler nor NIST.

You should update your position.

It's not wildly different from your previous position, as it's still valid to suggest ~1.75s of ~FFA during which the NW corner descends ~83ft.

Being more specific than that, or omitting any of the approximate qualifiers is not supported by my data, let alone the lower quality and inferior data from either Chandler or NIST.

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This is basic high school physics that most high school aged people can understand.

It is indeed. So why are you having so much difficulty with it ? Are you pre-high-school in learning ?

If so, then why are you trying to defend your eronious position ?

If not, then why are you trying to defend your eronious position ?

OCaptain · 30th June 2012, 07:50 AM

Originally Posted by Christopher7

Chandler explains what he did and what the software did. You ask for things you know don't exist and do not need to be known in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'.

Only deniers would do that. Chandler said "indistinguishable from free fall acceleration" and NIST said "at free fall"

NIST measured to within 1/10th of 1%. The difference is negligible - to small to be considered. As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100' and claiming that NIST and Chandler don't know what they are talking about I will continue to post these facts.

Double talk. Your implication in using ~ is that it is not FFA, correct? You can't have it both ways.

Irrelevant to the period of FFA.

On the velocity graph.

I just moved the line up to show how it fits the data before the moment of >g [which is probably a slight movement in the camera several miles away].

http://img37.imageshack.us/img37/7076/femr5ee.jpg

.

Christopher? We're talking about 2.25 seconds. No more than about 25% of the total collapse! You're obsessing over minutaie. Contrary to what you might think, the whole world doesn't hang on that 2.25 seconds!

Breathe! Chill out!

Dave Rogers · 30th June 2012, 01:57 PM

Originally Posted by Christopher7

The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration.

This is basic high school physics that most high school aged people can understand.

Bollocks. Basic high school physics says that, unless you've analysed and understood the measurement error of the individual points, you can't tell what level of detail in the data is a genuine measurement and what part is that inaccuracy. As usual, C7 is starting from a conclusion and reasoning backwards to an unfounded interpretation of the data. If he weren't, he'd be able to state the width of the error bar on each point, which he won't because he can't.

Dave

Christopher7 · 1st July 2012, 03:22 AM

Originally Posted by femr2

There is certainly an amount of error introduced by extracting the data from video, however, you do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one.

The software computes the average and draws the line. It is designed to compute the velocity of objects in a video and that's the way it's done.

In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA. Your data points are closer to the free fall line than Chandlers or NIST's. Nice work. Since data taken from a video is imprecise, a straight line thru the average of the data points is the logical scientific conclusion. That is the accepted way it is done.

Your interpretation that WTC 7 was varying around FFA is wrong.

Christopher7 · 1st July 2012, 03:53 AM

Originally Posted by femr2

My acceleration profile is much closer to actual, and reveals detail not presented by either Chandler nor NIST.

You used the same data for your acceleration and velocity graphs but got completely different results.

If you wish to claim that I am wrong, point to where I am wrong.

On your acceleration graph, you have
~0.8s of acceleration from zero to FFA
Then ~1 s of >g.
Then 0.5s of g or >g ???
Then <g

But on your velocity graph you have
~0.1s to 0.2s of acceleration from zero to FFA
Then ~0.4s of FFA
Then ~0.3s of >g
Then ~1.75s of g
Then <g

Animal · 1st July 2012, 06:36 AM

Originally Posted by Dave Rogers

Bollocks. Basic high school physics says that, unless you've analysed and understood the measurement error of the individual points, you can't tell what level of detail in the data is a genuine measurement and what part is that inaccuracy. As usual, C7 is starting from a conclusion and reasoning backwards to an unfounded interpretation of the data. If he weren't, he'd be able to state the width of the error bar on each point, which he won't because he can't.

Dave

Give him some slack

Every other one of his pet theories has been slapped around like a red headed step child. His "free fall" issue is the only one with fuzzy enough data to survive.

And of course he will continue to ignore the fact that even with "free fall" it does nothing to advance his absurd claim of explosive devices.

femr2 · 1st July 2012, 06:40 AM

Originally Posted by Christopher7

The software computes the average and draws the line.

It's a best fit, not the average as such. It's still a straight line placed over a wiggly one.

You do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one.

You can eliminate some noise using a variety of techniques, but you cannot remove it all.

All a best-fit linear regression gives you is an estimated average between two points in time.

All manner of real variation can occur during that time.

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It is designed to compute the velocity of objects in a video and that's the way it's done.

lol. It uses a simple symmetric difference calculation to derive to velocity.

Derivation can be performed in a number of ways.

The Savitzky-Golay smoothing method I use performs a mathematical differentiation of each curve fit function (which is very handy). There is one curve fit per sample. Hundreds of 'em.

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In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA.

Why don't you ask him, rather than guess ?

I have no great issue with folk suggesting ~1.75s of ~FFA during which the NW corner descended ~83ft.

Not one "~" is optional.

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Your data points are closer to the free fall line than Chandlers or NIST's.

Correct in places. In others further away.

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Nice work.

You're welcome. I do suggest you start listening to the interpretations that do not fit your chosen and preferred outcome.

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Since data taken from a video is imprecise

Correct, though for many different reasons. ALL measurement is imprecise. Many other noise sources exist.

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a straight line thru the average of the data points is the logical scientific conclusion.

Incorrect. That's simply an average, not a conclusion. An approximation.

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That is the accepted way it is done.

An accepted way, sure. However, that's by folk who have no problem stating APPROXIMATELY, AVERAGE, ...

You do have a problem with that, but it's YOUR problem.

Add the approximation qualifiers and you'll be fine.

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Your interpretation that WTC 7 was varying around FFA is wrong.

ROFL. Nonsense.

You actually think that a non-spherical object outside of a vacuum will "fall" AT FFA on the surface of this planet ?

Did you know an apple dropped from the roof would take >8s to hit the ground (In a vacuum it would be <6s)

You have NO WAY to determine acceleration with any more accuracy than I do. You can estimate. About FFA for a bit. Around FFA for a bit. Roughly FFA for a bit. Some >g

femr2 · 1st July 2012, 06:50 AM

Originally Posted by Christopher7

You used the same data for your acceleration and velocity graphs

Same source data, yes.

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but got completely different results.

Incorrect.

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If you wish to claim that I am wrong, point to where I am wrong.

I have told you numerous times already. You cannot correctly determine subtle acceleration behaviour from a velocity graph. Especially when you are looking at smoothed plots.

chrismohr · 1st July 2012, 10:09 AM

On chrismohr911.com, I have finished all 44 of my first points in the re-re-rebuttal section except for some links. Am open to suggestions on any corrections there. Thanks, Chris

Dowly · 1st July 2012, 04:47 PM

Thanks for the videos, Chris!

000063 · 1st July 2012, 07:06 PM

Originally Posted by Animal

Give him some slack

Every other one of his pet theories has been slapped around like a red headed step child. His "free fall" issue is the only one with fuzzy enough data to survive.

And of course he will continue to ignore the fact that even with "free fall" it does nothing to advance his absurd claim of explosive devices.

Experimental, top secret military explosives which were somehow developed in secret.

Literally every time he has advanced his actual theory, he gets spanked. Hence sticking to the minutae, where he is merely less obviously wrong.

Christopher7 · 2nd July 2012, 12:03 AM

Originally Posted by C7

You used the same data for your acceleration and velocity graphs

Originally Posted by femr2

Same source data, yes.

Originally Posted by C7

but got completely different results.

Incorrect.

??? This is not "subtle acceleration behavior", these results are entirely different.

On your acceleration graph, you have
~0.8s of acceleration from zero to FFA
Then ~1 s of >g.
Then 0.5s of g or >g ???
Then <g

But on your velocity graph you have
~0.1s to 0.2s of acceleration from zero to FFA
Then ~0.4s of FFA
Then ~0.3s of >g
Then ~1.75s of g
Then <g

Christopher7 · 2nd July 2012, 12:35 AM

Originally Posted by femr2

It's a best fit, not the average as such. It's still a straight line placed over a wiggly one.

The wiggly line is a figment of your imagination, a deliberate misinterpretation of the data. The data points are not accurate because they are taken from a video and you know it.

Originally Posted by C7

It is designed to compute the velocity of objects in a video and that's the way it's done.

Quote:

It uses a simple symmetric difference calculation to derive to velocity.

This is very simple high school physics.

Originally Posted by C7

In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA.

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Why don't you ask him, rather than guess ?

You ignored the point which is: He acknowledges FFA for 1.75s.

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Not one "~" is optional.

Only in the denoir choir. The deviation from FFA is to small to be considered. That's why NIST said "at gravitational acceleration" and Chandler said "indistinguishable from FFA".

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I do suggest you start listening to the interpretations that do not fit your chosen and preferred outcome.

Speak for yourself. I am just repeating what NIST and Chandler said. They know what they are talking about and you don't.

Originally Posted by C7

Your interpretation that WTC 7 was varying around FFA is wrong.

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ROFL. Nonsense.

OK. Your interpretation that WTC 7 was varying around FFA is nonsense.

femr2 · 2nd July 2012, 12:43 AM

Originally Posted by Christopher7

??? This is not "subtle acceleration behavior", these results are entirely different.

That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed.

femr2 · 2nd July 2012, 12:58 AM

Originally Posted by Christopher7

The wiggly line is a figment of your imagination

Incorrect.

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a deliberate misinterpretation of the data.

It is the data on a graph.

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The data points are not accurate because they are taken from a video and you know it.

I do indeed, however, noise doesn't dictate trend.

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This is very simple high school physics.

The mathematics, sure.

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You ignored the point which is: He acknowledges FFA for 1.75s.

He omitted an approximation qualifier. I'll have a word.

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The deviation from FFA is to small to be considered.

Incorrect. There WAS deviation, therefore you MUST state as approximate, NOT at.

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That's why NIST said "at gravitational acceleration"

Quote mine. The context is clear, and I've told you many times. Your continued use of such simply highlights that either you're too stupid to realise that repeating the words as explicit fact on their own is erronious, or you do understand and do it deliberately. Either way, shame on you.

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and Chandler said "indistinguishable from FFA".

Which he shouldn't have...

...and anyway, that's not AT, which is what YOU keep saying

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I am just repeating what NIST and Chandler said.

Not really.

Christopher7 · 2nd July 2012, 01:01 AM

Originally Posted by femr2

That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed.

Interpret?
0.8s is quite different from 0.1 or 0.2s etc.
How do you interpret the data? Give numbers please.
Say what each part is and how long it lasted as I have done.

You have stated that the >g lasted ~1s but you have also said that it was ~0.5s. Indeed, that is close to what your graphs show. You cannot have two different sets of results from one set of data.

femr2 · 2nd July 2012, 01:18 AM

Originally Posted by Christopher7

Interpret?

Yes.

Quote:

How do you interpret the data? Give numbers please.

Have done, several times...

Originally Posted by femr2

My acceleration graph shows:

a) Rapid increase in acceleration from release to somewhat over-g in approximately 1s.

At the end of this period, the NW corner had descended ~9ft

b) Slow reduction in acceleration to approximately g over approximately 1.5s.

At the end of this period, the NW corner had descended ~83ft

c) More rapid reduction in acceleration to roughly constant velocity over approximately 2s.

At the end of this period, the NW corner had descended ~270ft

If you use the velocity graph...

...you'll obviously miss some profile shape detail, but you could say...

~1.75s at ~FFA (and I'd not complain too much)

I'd be okay with... ~1.75s of ~FFA, of which >~0.5s is over-g ... for the NW corner.

Animal · 2nd July 2012, 01:21 AM

Originally Posted by femr2

Originally Posted by Christopher7

Quote:

??? This is not "subtle acceleration behavior", these results are entirely different.

That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed.

That is one thing you can depend on from C7

Christopher7 · 2nd July 2012, 01:23 AM

Originally Posted by C7

The deviation from FFA is to small to be considered.

Originally Posted by femr2

Incorrect. There WAS deviation, therefore you MUST state as approximate, NOT at.

I must? Who put you in charge?
NIST didn't, Chandler didn't, and neither does anyone outside the denoir choir.

Talk to yourself much?
"approximately" "estimation" "equivalent" [ignore the conclusion of "at gravitational acceleration" after the qualifiers about the data]
Quote mine. The context is clear, and I've told you many times. Your continued use of such simply highlights that either you're too stupid to realize that repeating the words as explicit fact on their own is erroneous, or you do understand and do it deliberately. Either way, shame on you.

Originally Posted by C7

and Chandler said "indistinguishable from FFA".

Quote:

Which he shouldn't have...

Who are you to say? He has a BS in physics, a masters degree in math, a masters degree in teaching and 20 to 30 years of experience. You are an anonymous poster with nothing but a lot of bombastic babble and denial.

Christopher7 · 2nd July 2012, 01:38 AM

Originally Posted by femr2

Yes.
Have done, several times...

Acceleration graph
a. release to somewhat over-g in approximately 1s.
b. reduction in acceleration to approximately g over approximately 1.5s.
c. reduction in acceleration to [<g]
There is NO ~1.75s of ~FFA

Velocity graph
You don't give values for:
a. ?
b. ?
c. ?
Just:
~1.75s at ~FFA

Same data - 2 entirely different results.

Dave Rogers · 2nd July 2012, 01:56 AM

Originally Posted by Christopher7

The software computes the average and draws the line. It is designed to compute the velocity of objects in a video and that's the way it's done.

I realise that there's little point trying to push back the vast Sahara of ignorance that blankets C7's understanding of this topic, but as usual that statement is such a colossal over-simplification that it's reduced to an absurdity. The purpose of a straight line fit is to determine a rate of change over a period of time based on the assumption that the said rate of change is constant over that period of time. C7's insistence that the straight line fit proves that the acceleration was constant over the time covered by the fit is classic circular reasoning.

Dave

Christopher7 · 2nd July 2012, 02:24 AM

Originally Posted by Dave Rogers

The purpose of a straight line fit is to determine a rate of change over a period of time based on the assumption that the said rate of change is constant over that period of time. C7's insistence that the straight line fit proves that the acceleration was constant over the time covered by the fit is classic circular reasoning.

My insistence? No. That is NIST and Chandler's conclusion.

Dave Rogers · 2nd July 2012, 02:52 AM

Originally Posted by Christopher7

My insistence? No. That is NIST and Chandler's conclusion.

Chandler is an idiot, so I care very little what he concludes. I would suggest you post the exact wording of what you imagine to be NIST's conclusion, so that I can explain to you which bit you don't understand. And make sure you get the wording right, because someone's sure to notice if you change it.

Dave

femr2 · 2nd July 2012, 04:47 AM

Originally Posted by Dave Rogers

I would suggest you post the exact wording of what you imagine to be NIST's conclusion

======
Figure 12–76 presents a plot of the downward displacement data shown as solid circles. A curve fit is also plotted with these data as a solid line. A function of the form z(t) = A{1 – exp[–(t/λ)^k]} was selected because it is flexible and well-behaved, and because it satisfies the initial conditions of zero displacement, zero velocity, and zero acceleration. The constants A, λ, and k were determined using least squares fitting. The fitted displacement function was differentiated to estimate the downward velocity as a function of time, shown as a solid curve in Figure 12–77. Velocity data points (solid circles) were also determined from the displacement data using a central difference approximation¹. The slope of the velocity curve is approximately constant between about 1.75 s and 4.0 s. To estimate the downward acceleration² during this stage, a straight line was fit to the open-circled velocity data points using linear regression (shown as a straight line in Figure 12–77). The slope of the straight line, which represents a constant acceleration, was found to be 32.2 ft/s² (with a coefficient of regression R² = 0.991), equivalent to the acceleration of gravity g. Note that this line closely matches the velocity curve between about 1.75 s and 4.0 s.

For discussion purposes, three stages were defined
======

femr2 · 2nd July 2012, 05:17 AM

Originally Posted by Christopher7

I must?

Everyone must (include approximate qualifiers when discussing WTC7 acceleration metrics).

Quote:

NIST didn't

Incorrect.

Quote:

Chandler didn't

Incorrect.

Quote:

"approximately" "estimation" "equivalent"

Correct.

Quote:

[ignore the conclusion of "at gravitational acceleration" after the qualifiers about the data]

Incorrect. Simply ensure the qualifiers are included (or preface simplified summary with such)

28th June 2012, 06:29 AM	#5681
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by pgimeno Approximately constant distance (or with a negligible percent in variation, as in the case of the Dan Rather viewpoint) results in negligible need for correction. Agreed. The correction is of lower magnitude than the error resulting from defining building scaling metric on the Dan Rather footage, so it's a bit pointless. Quote: With that 3D info it would then be possible to perform full perspective correction. I could use SynthEyes to resolve the 3D motion using multiple "shots", but the problem with that (automated route AND manual as you're describing) is the significant increase in noise. Quote: I'm interested in the shape of the curve for the first moments. Not a problem. Quote: There's little N-S movement at that point. I haven't compared the height of the windows near the bottom with that near the top; that can also give an idea of the influence of perspective. It's fairly small, but not negligible.
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28th June 2012, 06:45 AM	#5682
pgimeno Graduate Poster Join Date: Feb 2009 Location: Spain Posts: 1,320	Originally Posted by femr2 I could use SynthEyes to resolve the 3D motion using multiple "shots", but the problem with that (automated route AND manual as you're describing) is the significant increase in noise. The aim I had in mind is not to use a 3D trace for graphing, only for estimating distance to the camera over time for perspective correction. I expect that a heavily smoothed version of the 3D trace would suffice for that purpose. Microscale movements have negligible influence in the perspective correction. It would just be an additional refinement to the vertical position data. Originally Posted by femr2 [Influence of perspective is] fairly small, but not negligible. Mostly agreed. That's why I've suggested using the camera position for the correction; the distance between the windows can serve as a secondary check, and also to have an initial idea before going into the more complex calculations.
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28th June 2012, 11:51 AM	#5683
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 Use your words. A YT link does not answer your assertions about NIST and Chandler. Chandler explains what he did and what the software did. You ask for things you know don't exist and do not need to be known in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'. Quote: Then you'll have no issue adding a ~ prefix to your "FFA" every time you state it then. Only deniers would do that. Chandler said "indistinguishable from free fall acceleration" and NIST said "at free fall" NIST measured to within 1/10th of 1%. The difference is negligible - to small to be considered. As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100' and claiming that NIST and Chandler don't know what they are talking about I will continue to post these facts. Quote: A while since I've been called a "denier". Denying what ? No-one is denying a period of ~FFA. It's the ~ that's important there. Double talk. Your implication in using ~ is that it is not FFA, correct? You can't have it both ways. Quote: What caused early motion of the building, as-in...the building was in motion long before it started to drop. What caused that motion ? Irrelevant to the period of FFA. Originally Posted by C7 Draw the line that shows your interpretation. http://img515.imageshack.us/img515/2535/femr5e.jpg Quote: Sure... http://femr2.ucoz.com/_ph/7/2/447669743.jpg On the velocity graph. I just moved the line up to show how it fits the data before the moment of >g [which is probably a slight movement in the camera several miles away]. .
	Last edited by Christopher7; 28th June 2012 at 11:55 AM.

28th June 2012, 12:21 PM	#5684
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 Chandler explains what he did and what the software did. Yet you are unable to type them. Big surprise. Quote: You ask for things you know don't exist Incorrect. I've told you the answers several times within this very thread. It seems you're simply too dense to even notice. Quote: and do not need to be known When you repeatedly say stupid things like... Originally Posted by Christopher7 The programs NIST and Chandler used were designed to calculate acceleration. ...whilst freely admitting, when asked what "programs" they use. that... Originally Posted by Christopher7 [you] don't know. That's just dumb. Again, I've TOLD you numerous times... Originally Posted by femr2 You don't know what "programs" were used, because you simply don't understand. I've told you what I use: a) SynthEyes - Professional feature tracking system, which I use to extract motion data from video with high precision. I've used many similar systems and SynthEyes has by far the most accurate tracking engine. b) OriginPro - Professional data analysis and math environment, which I use to perform Savitzky-Golay smoothed derivation of raw data. c) Excel - Which I use to translate from pixel units to real-world units, and generate the many lovely graphs I post. Now then... NIST placed "dots" on video by hand. So did Chandler. Awful. Chandler may have redone his trace with Tracker, but likely did not use it's primitive tracking facilities. NIST derived data using simple central difference approximation, probably with Excel or Matlab, though a piece of paper would do. Chandler's freebies "Physics Toolkit/Tracker" performed a similar symmetric difference derivation. Yet you STILL don't know. Yet you still keep saying the "programs" they used "were designed to measure velocity and acceleration". Bizarre. So, comprehension test...have a go at answering my questions again. Quote: in an attempt to claim that NIST and Chandler don't know what they are talking about As I already said to you, YOU don't even understand what they ARE saying. I've repeatedly told you that it's not about them not knowing what they are talking about, simply that their analyses use low fidelity data, and their results are inaccurate. What part of that do you not understand ? Quote: when they said WTC 7 fell at free fall for ~100'. Firstly, NIST don't say that. With local context... ...NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period. Quote: Only deniers would do that. lol. Quote: Chandler said "indistinguishable from free fall acceleration" ~FFA. Quote: and NIST said "at free fall" Nah... NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period. Quote: As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100' What is wrong with you ? No-one is denying ~FFA for a period of time, indeed I am ADDING a period >FFA. What part of that are you having a problem with ? Quote: and claiming that NIST and Chandler don't know what they are talking about Where do I claim such ? I highlight problems with their data and studies, absolutely, as those issues are all real. Quote: I will continue to post these facts. You're not posting "facts". You're posting "crap". You know you're posting crap. Transparent. Obvious. Quote: Double talk. Your implication in using ~ is that it is not FFA, correct? Jebus. What does "~" mean ? Quote: You can't have it both ways. lol. Quote: Irrelevant to the period of FFA. ~FFA. ffs. Quote: On the velocity graph The line indicating ~FFA is already on the graph son. Quote: I just moved the line up to show how it fits the data It doesn't fit. You don't know what you're doing. Stop it.
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28th June 2012, 01:01 PM	#5685
DGM #4 Join Date: May 2007 Location: West of Northshore MA Posts: 14,535	Originally Posted by Christopher7 and NIST said "at free fall" . No, they didn't. Wouldn't that make you a fraud? Let me guess, you subscribe to the belief it's OK to "lie for truth".
	__________________ Join the team, Show us what your machine can do (or just contribute to a good cause)Join the JREF Folders ! Team 13232 "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley Last edited by DGM; 28th June 2012 at 01:03 PM.

28th June 2012, 02:40 PM	#5686
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 Firstly, NIST don't say that. With local context... ...NIST say their estimation of approximate and average acceleration is equivalent to the acceleration of gravity during that period. You hang you hat on the qualifiers and ignore the scientific conclusion. "the north face descended at gravitational acceleration" ~~~FFA.~~ FFA The difference is so tiny that it is not worth considering. Only a devout denier would try to imply that it is not FFA. Originally Posted by C7 claiming that NIST and Chandler don't know what they are talking about Quote: Where do I claim such ? I highlight problems with their data and studies, absolutely, as those issues are all real. You just did. Quote: What does "~" mean ? That was the question. When you use ~ does that mean that it was NOT FFA? Quote: The line indicating ~FFA is already on the graph. Non answer. You say there is .5s of >g. Where? draw lines to indicate where it is. Quote: It doesn't fit. Yes it does. It fits as well as the 1.8s of g. The data points are not perfect because they are taken from a video. You have acknowledged that. In any case, the first 0.7s are at or greater than FFA. i.e. NO RESISTANCE!

28th June 2012, 02:47 PM	#5687
GlennB Jellied eel and offal fancier Join Date: Sep 2006 Location: Arcadia Posts: 9,213	And C7 will argue forever and a day about sub-pixel levels of accuracy in video analysis while blithely ignoring the absence of the 000's of explosions required to support his weird theory. "Straining at gnats" is a good expression, and sums him up well.

28th June 2012, 03:21 PM	#5688
DGM #4 Join Date: May 2007 Location: West of Northshore MA Posts: 14,535	Originally Posted by GlennB And C7 will argue forever and a day about sub-pixel levels of accuracy in video analysis while blithely ignoring the absence of the 000's of explosions required to support his weird theory. "Straining at gnats" is a good expression, and sums him up well. You would almost expect Chris7 to post page after page of traces of buildings destroyed by controlled demolition falling at "free fall", but, he does not. Why is this Chris7? This is a "classic sign" of controlled demolition, right?
	__________________ Join the team, Show us what your machine can do (or just contribute to a good cause)Join the JREF Folders ! Team 13232 "Remember that the goal of conspiracy rhetoric is to bog down the discussion, not to make progress toward a solution" Jay Windley

28th June 2012, 04:50 PM	#5689
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 You hang you hat on the qualifiers and ignore the scientific conclusion. Incorrect. Quote: ~~~FFA.~~ Incorrect. Quote: The difference is so tiny that it is not worth considering. Incorrect. Quote: Only a devout denier would try to imply that it is not FFA. Incorrect. Quote: You just did. Incorrect. Quote: That was the question. When you use ~ does that mean that it was NOT FFA? Really ? "~" = "approximately". Quote: Non answer. Incorrect. Quote: You say there is .5s of >g Incorrect. ~0.5s. Quote: Where? draw lines to indicate where it is. No need. Use the acceleration graph. Anything below ~-32.2ft/s² is >g. Quote: Yes it does. Incorrect. Quote: It fits as well as the 1.8s of g. Incorrect. Quote: The data points are not perfect because they are taken from a video. Partially correct. Quote: You have acknowledged that. Correct ! Quote: In any case, the first 0.7s are at or greater than FFA Incorrect. Quote: i.e. NO RESISTANCE! Incorrect. 11 Incorrect. 1 Correct. 3 Middlin' You do not win a prize. Try harder next time.
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28th June 2012, 10:37 PM	#5690
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by C7 That was the question. When you use ~ does that mean that it was NOT FFA? Originally Posted by femr2 Really ? "~" = "approximately". Non answer. When you use ~/approximately do you mean it was not FFA ? Originally Posted by C7 Where? draw lines to indicate where it is. Quote: No need. Use the acceleration graph. Anything below ~-32.2ft/s² is >g. Cop-out. I have shown that your velocity graph shows: ETC: FFA for ~0.4s, then >g for ~0.3s. then FFA for 1.8s. You cannot refute this so you refuse to answer directly. We could quibble about 0.2s of >g but that's not the point. Your velocity graph shows FFA or greater. There is NO <g until 14.9s - 85'. Just saying incorrect without saying why is worthless.
	Last edited by Christopher7; 29th June 2012 at 12:35 AM.

29th June 2012, 02:35 AM	#5691
Oystein Philosopher Join Date: Dec 2009 Location: Germany Posts: 9,930	Originally Posted by Christopher7 ... No, the data points [dots] are inaccurate due to the fact they are taken from a video. Some are more inaccurate than others. That's why the program has a feature that computes the average and draws the line. ... C7, do you have Chandler's data points in tabulated form? As a list of pairs of numerical values "time\|drop distance"? This as opposed to "dots" or "lines" drawn in a chart. Thanks

29th June 2012, 04:36 AM	#5692
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 Non answer. Incorrect. Quote: When you use ~/approximately do you mean it was not FFA ? The inclusion of the approximate qualifier is non-optional, and means just that...approximate. You, as you are clearly a bit dim, might want to think of some other words, like equivalent, estimation, average...things like that. Stick a ~ in front of "FFA" when you write it, and I'll give you a lot less grief. Oh, but make sure you don't state ridiculous incorrect ~FFA periods suggesting my data supports your nonsense, as it doesn't. Being very generous you could say my data suggests ~1.75s of ~FFA. More than that and I'll be on your case. Quote: I have shown that your velocity graph shows You really haven't. Quote: You cannot refute this so you refuse to answer directly. ROFL. My graph shows there are Klingons on the starboard bow. You cannot refute this so you must now sit in the corner wearing the blue dunce hat. Refute what ? You pulling faeces out of thin air ? I've tried to tell you many times. The time to simply point and laugh instead is approaching rapidly I'm afraid. Quote: We could quibble about 0.2s of >g but that's not the point. No, the point is that your severe lack of understanding, in combination with your willful refusal to learn from (or even admit) (or, ffs, even recognise) your mistakes, in conjunction to your blind desire to see what you want to see...renders your dialogue totally pointless, repetative and really, really boring. Without your problems above, you could have simply improved your understanding a long time ago, and be discussing the correct details, rather than waste my time going round in circles with the REALLY simplest of friggin things imaginable. Quote: Just saying incorrect without saying why is worthless. Saves me time. It's not like you're ever going to learn anything. You just don't want to.
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29th June 2012, 05:49 PM	#5693
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'. Here's Chandler's "re-done" WTC7 velocity plot... In your own words, please explain how the **** you get from that remarkably non-linear (aka wiggly) line, which, of course you understand cannot imply a constant acceleration, "FFA" or not, to saying "indistinguishable from freefall" ? Quote: Chandler said "indistinguishable from free fall acceleration" Correct. He really shouldn't have, should he.
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30th June 2012, 01:36 AM	#5694
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 Here's Chandler's "re-done" WTC7 velocity plot... http://femr2.ucoz.com/_ph/7/117268871.png In your own words, please explain how the **** you get from that remarkably non-linear (aka wiggly) line, which, of course you understand cannot imply a constant acceleration, "FFA" or not, to saying "indistinguishable from freefall" ? The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration. This is basic high school physics that most high school aged people can understand.

30th June 2012, 01:40 AM	#5695
ozeco41 Illuminator Join Date: Mar 2009 Location: Moss Vale, NSW, Australia Posts: 3,656	Originally Posted by Christopher7 The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration. This is basic high school physics that most high school aged people can understand. Chandler versus femr2 ??? My money is on femr2. ...even us older folk understand physics. But we weren't "taught" by Chandler.

30th June 2012, 04:14 AM	#5696
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 The wiggly line assumes that the data points are accurate. The "wiggly line" is not sentient, and assumes nothing. The line simply connects the actual data-points. The RESULT is a "wiggly line". Quote: Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. There is certainly an amount of error introduced by extracting the data from video, however, you do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one. All you achieve is an average, an estimation, an approximate result that is easier to "read". The question you must ask, is how you KNOW that variation is "noise" and not "real" ? The answer, as I know you'll fluff it, is that you don't know. There are ways of "cutting through noise", but a linear fit is FAR from the best or most accurate way to do that. Quote: The deviation from free fall line is that inaccuracy, not a variation in the acceleration. Utterly, obviously, simply incorrect...in this case, as we DO have more accurate data available, mine. My data shows that some of that variation is indeed "real". My acceleration profile is much closer to actual, and reveals detail not presented by either Chandler nor NIST. You should update your position. It's not wildly different from your previous position, as it's still valid to suggest ~1.75s of ~FFA during which the NW corner descends ~83ft. Being more specific than that, or omitting any of the approximate qualifiers is not supported by my data, let alone the lower quality and inferior data from either Chandler or NIST. Quote: This is basic high school physics that most high school aged people can understand. It is indeed. So why are you having so much difficulty with it ? Are you pre-high-school in learning ? If so, then why are you trying to defend your eronious position ? If not, then why are you trying to defend your eronious position ?
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30th June 2012, 07:50 AM	#5697
OCaptain Muse Join Date: Aug 2011 Posts: 917	Originally Posted by Christopher7 Chandler explains what he did and what the software did. You ask for things you know don't exist and do not need to be known in an attempt to claim that NIST and Chandler don't know what they are talking about when they said WTC 7 fell at free fall for ~100'. Only deniers would do that. Chandler said "indistinguishable from free fall acceleration" and NIST said "at free fall" NIST measured to within 1/10th of 1%. The difference is negligible - to small to be considered. As long as you keep using sophistry to deny the fact that WTC 7 fell at free fall acceleration for about 100' and claiming that NIST and Chandler don't know what they are talking about I will continue to post these facts. Double talk. Your implication in using ~ is that it is not FFA, correct? You can't have it both ways. Irrelevant to the period of FFA. On the velocity graph. I just moved the line up to show how it fits the data before the moment of >g [which is probably a slight movement in the camera several miles away]. http://img37.imageshack.us/img37/7076/femr5ee.jpg . Christopher? We're talking about 2.25 seconds. No more than about 25% of the total collapse! You're obsessing over minutaie. Contrary to what you might think, the whole world doesn't hang on that 2.25 seconds! Breathe! Chill out!
OCaptain Muse Join Date: Aug 2011 Posts: 917

30th June 2012, 01:57 PM	#5698
Dave Rogers Bandaged ice that stampedes inexpensively through a scribbled morning waving necessary ankles Join Date: Jan 2007 Location: In a world lit only by fire. Posts: 17,907	Originally Posted by Christopher7 The wiggly line assumes that the data points are accurate. Chandler explains that the data points are not perfectly accurate because they are taken from a grainy video. The deviation from free fall line is that inaccuracy, not a variation in the acceleration. This is basic high school physics that most high school aged people can understand. Bollocks. Basic high school physics says that, unless you've analysed and understood the measurement error of the individual points, you can't tell what level of detail in the data is a genuine measurement and what part is that inaccuracy. As usual, C7 is starting from a conclusion and reasoning backwards to an unfounded interpretation of the data. If he weren't, he'd be able to state the width of the error bar on each point, which he won't because he can't. Dave
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1st July 2012, 03:22 AM	#5699
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 There is certainly an amount of error introduced by extracting the data from video, however, you do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one. The software computes the average and draws the line. It is designed to compute the velocity of objects in a video and that's the way it's done. In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA. Your data points are closer to the free fall line than Chandlers or NIST's. Nice work. Since data taken from a video is imprecise, a straight line thru the average of the data points is the logical scientific conclusion. That is the accepted way it is done. Your interpretation that WTC 7 was varying around FFA is wrong.

1st July 2012, 03:53 AM	#5700
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 My acceleration profile is much closer to actual, and reveals detail not presented by either Chandler nor NIST. You used the same data for your acceleration and velocity graphs but got completely different results. If you wish to claim that I am wrong, point to where I am wrong. On your acceleration graph, you have ~0.8s of acceleration from zero to FFA Then ~1 s of >g. Then 0.5s of g or >g ??? Then <g But on your velocity graph you have ~0.1s to 0.2s of acceleration from zero to FFA Then ~0.4s of FFA Then ~0.3s of >g Then ~1.75s of g Then <g
	Last edited by Christopher7; 1st July 2012 at 03:56 AM.

1st July 2012, 06:36 AM	#5701
Animal Graduate Poster Join Date: Feb 2011 Location: SE Michigan Posts: 1,368	Originally Posted by Dave Rogers Bollocks. Basic high school physics says that, unless you've analysed and understood the measurement error of the individual points, you can't tell what level of detail in the data is a genuine measurement and what part is that inaccuracy. As usual, C7 is starting from a conclusion and reasoning backwards to an unfounded interpretation of the data. If he weren't, he'd be able to state the width of the error bar on each point, which he won't because he can't. Dave Give him some slack Every other one of his pet theories has been slapped around like a red headed step child. His "free fall" issue is the only one with fuzzy enough data to survive. And of course he will continue to ignore the fact that even with "free fall" it does nothing to advance his absurd claim of explosive devices.

1st July 2012, 06:40 AM	#5702
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 The software computes the average and draws the line. It's a best fit, not the average as such. It's still a straight line placed over a wiggly one. You do not create new accuracy that was not there in the first place by placing a straight line over the top of a wiggly one. You can eliminate some noise using a variety of techniques, but you cannot remove it all. All a best-fit linear regression gives you is an estimated average between two points in time. All manner of real variation can occur during that time. Quote: It is designed to compute the velocity of objects in a video and that's the way it's done. lol. It uses a simple symmetric difference calculation to derive to velocity. Derivation can be performed in a number of ways. The Savitzky-Golay smoothing method I use performs a mathematical differentiation of each curve fit function (which is very handy). There is one curve fit per sample. Hundreds of 'em. Quote: In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA. Why don't you ask him, rather than guess ? I have no great issue with folk suggesting ~1.75s of ~FFA during which the NW corner descended ~83ft. Not one "~" is optional. Quote: Your data points are closer to the free fall line than Chandlers or NIST's. Correct in places. In others further away. Quote: Nice work. You're welcome. I do suggest you start listening to the interpretations that do not fit your chosen and preferred outcome. Quote: Since data taken from a video is imprecise Correct, though for many different reasons. ALL measurement is imprecise. Many other noise sources exist. Quote: a straight line thru the average of the data points is the logical scientific conclusion. Incorrect. That's simply an average, not a conclusion. An approximation. Quote: That is the accepted way it is done. An accepted way, sure. However, that's by folk who have no problem stating APPROXIMATELY, AVERAGE, ... You do have a problem with that, but it's YOUR problem. Add the approximation qualifiers and you'll be fine. Quote: Your interpretation that WTC 7 was varying around FFA is wrong. ROFL. Nonsense. You actually think that a non-spherical object outside of a vacuum will "fall" AT FFA on the surface of this planet ? Did you know an apple dropped from the roof would take >8s to hit the ground (In a vacuum it would be <6s) You have NO WAY to determine acceleration with any more accuracy than I do. You can estimate. About FFA for a bit. Around FFA for a bit. Roughly FFA for a bit. Some >g
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1st July 2012, 06:50 AM	#5703
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 You used the same data for your acceleration and velocity graphs Same source data, yes. Quote: but got completely different results. Incorrect. Quote: If you wish to claim that I am wrong, point to where I am wrong. I have told you numerous times already. You cannot correctly determine subtle acceleration behaviour from a velocity graph. Especially when you are looking at smoothed plots.
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1st July 2012, 10:09 AM	#5704
chrismohr Graduate Poster Join Date: Mar 2011 Posts: 1,364	On chrismohr911.com, I have finished all 44 of my first points in the re-re-rebuttal section except for some links. Am open to suggestions on any corrections there. Thanks, Chris
	__________________ 20 videos rebutting Blueprint for Truth YouTube keyword chrismohr911 http://www.youtube.com/watch?v=jC3JgWkNNIQ Playlists http://www.youtube.com/playlist?list...eature=viewall and http://www.youtube.com/playlist?list...eature=viewall WTC Dust study http://dl.dropbox.com/u/64959841/911...12webHiRes.pdf Hundreds more links and info both sides: http:www.chrismohr911.com

1st July 2012, 04:47 PM	#5705
Dowly New Blood Join Date: Jun 2012 Location: Eastern Finland Posts: 5	Thanks for the videos, Chris!

1st July 2012, 07:06 PM	#5706
000063 Illuminator Join Date: Apr 2011 Location: Not America. Posts: 4,739	Originally Posted by Animal Give him some slack Every other one of his pet theories has been slapped around like a red headed step child. His "free fall" issue is the only one with fuzzy enough data to survive. And of course he will continue to ignore the fact that even with "free fall" it does nothing to advance his absurd claim of explosive devices. Experimental, top secret military explosives which were somehow developed in secret. Literally every time he has advanced his actual theory, he gets spanked. Hence sticking to the minutae, where he is merely less obviously wrong.
	__________________ No, I'd like you to answer the question in two, simple, coherent sentences. ... That's how you present credible arguments in written form. -ergo, on me giving him a 2 digit number I can think of two reasons why bedunkers are often so loathe to explain their theories using plain, concise language--words even. - ergo

2nd July 2012, 12:03 AM	#5707
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by C7 You used the same data for your acceleration and velocity graphs Originally Posted by femr2 Same source data, yes. Originally Posted by C7 but got completely different results. Incorrect. ??? This is not "subtle acceleration behavior", these results are entirely different. On your acceleration graph, you have ~0.8s of acceleration from zero to FFA Then ~1 s of >g. Then 0.5s of g or >g ??? Then <g But on your velocity graph you have ~0.1s to 0.2s of acceleration from zero to FFA Then ~0.4s of FFA Then ~0.3s of >g Then ~1.75s of g Then <g

2nd July 2012, 12:35 AM	#5708
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 It's a best fit, not the average as such. It's still a straight line placed over a wiggly one. The wiggly line is a figment of your imagination, a deliberate misinterpretation of the data. The data points are not accurate because they are taken from a video and you know it. Originally Posted by C7 It is designed to compute the velocity of objects in a video and that's the way it's done. Quote: It uses a simple symmetric difference calculation to derive to velocity. This is very simple high school physics. Originally Posted by C7 In the debate, Dave acknowledged "there was a 2 er 1 3/4 second period of FFA of this outer shell". He's probably referring to your graph and he understands that it confirms at least 1.75s of FFA. Quote: Why don't you ask him, rather than guess ? You ignored the point which is: He acknowledges FFA for 1.75s. Quote: Not one "~" is optional. Only in the denoir choir. The deviation from FFA is to small to be considered. That's why NIST said "at gravitational acceleration" and Chandler said "indistinguishable from FFA". Quote: I do suggest you start listening to the interpretations that do not fit your chosen and preferred outcome. Speak for yourself. I am just repeating what NIST and Chandler said. They know what they are talking about and you don't. Originally Posted by C7 Your interpretation that WTC 7 was varying around FFA is wrong. Quote: ROFL. Nonsense. OK. Your interpretation that WTC 7 was varying around FFA is nonsense.
	Last edited by Christopher7; 2nd July 2012 at 12:40 AM.

2nd July 2012, 12:43 AM	#5709
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 ??? This is not "subtle acceleration behavior", these results are entirely different. That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed.
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2nd July 2012, 12:58 AM	#5710
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 The wiggly line is a figment of your imagination Incorrect. Quote: a deliberate misinterpretation of the data. It is the data on a graph. Quote: The data points are not accurate because they are taken from a video and you know it. I do indeed, however, noise doesn't dictate trend. Quote: This is very simple high school physics. The mathematics, sure. Quote: You ignored the point which is: He acknowledges FFA for 1.75s. He omitted an approximation qualifier. I'll have a word. Quote: The deviation from FFA is to small to be considered. Incorrect. There WAS deviation, therefore you MUST state as approximate, NOT at. Quote: That's why NIST said "at gravitational acceleration" Quote mine. The context is clear, and I've told you many times. Your continued use of such simply highlights that either you're too stupid to realise that repeating the words as explicit fact on their own is erronious, or you do understand and do it deliberately. Either way, shame on you. Quote: and Chandler said "indistinguishable from FFA". Which he shouldn't have... ...and anyway, that's not AT, which is what YOU keep saying Quote: I am just repeating what NIST and Chandler said. Not really.
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2nd July 2012, 01:01 AM	#5711
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed. Interpret? 0.8s is quite different from 0.1 or 0.2s etc. How do you interpret the data? Give numbers please. Say what each part is and how long it lasted as I have done. You have stated that the >g lasted ~1s but you have also said that it was ~0.5s. Indeed, that is close to what your graphs show. You cannot have two different sets of results from one set of data.

2nd July 2012, 01:18 AM	#5712
femr2 Illuminator Join Date: Apr 2009 Location: UK Posts: 3,627	Originally Posted by Christopher7 Interpret? Yes. Quote: How do you interpret the data? Give numbers please. Have done, several times... Originally Posted by femr2 My acceleration graph shows: a) Rapid increase in acceleration from release to somewhat over-g in approximately 1s. At the end of this period, the NW corner had descended ~9ft b) Slow reduction in acceleration to approximately g over approximately 1.5s. At the end of this period, the NW corner had descended ~83ft c) More rapid reduction in acceleration to roughly constant velocity over approximately 2s. At the end of this period, the NW corner had descended ~270ft If you use the velocity graph... ...you'll obviously miss some profile shape detail, but you could say... ~1.75s at ~FFA (and I'd not complain too much) I'd be okay with... ~1.75s of ~FFA, of which >~0.5s is over-g ... for the NW corner.
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2nd July 2012, 01:21 AM	#5713
Animal Graduate Poster Join Date: Feb 2011 Location: SE Michigan Posts: 1,368	Originally Posted by femr2 Originally Posted by Christopher7 Quote: ??? This is not "subtle acceleration behavior", these results are entirely different. That is your interpretation of the plots. That has very little to do with the results. Your interpretation is rather flawed. That is one thing you can depend on from C7

2nd July 2012, 01:23 AM	#5714
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by C7 The deviation from FFA is to small to be considered. Originally Posted by femr2 Incorrect. There WAS deviation, therefore you MUST state as approximate, NOT at. I must? Who put you in charge? NIST didn't, Chandler didn't, and neither does anyone outside the denoir choir. Talk to yourself much? "approximately" "estimation" "equivalent" [ignore the conclusion of "at gravitational acceleration" after the qualifiers about the data] Quote mine. The context is clear, and I've told you many times. Your continued use of such simply highlights that either you're too stupid to realize that repeating the words as explicit fact on their own is erroneous, or you do understand and do it deliberately. Either way, shame on you. Originally Posted by C7 and Chandler said "indistinguishable from FFA". Quote: Which he shouldn't have... Who are you to say? He has a BS in physics, a masters degree in math, a masters degree in teaching and 20 to 30 years of experience. You are an anonymous poster with nothing but a lot of bombastic babble and denial.
	Last edited by Christopher7; 2nd July 2012 at 01:39 AM.

2nd July 2012, 01:38 AM	#5715
Christopher7 Philosopher Join Date: Aug 2006 Posts: 6,535	Originally Posted by femr2 Yes. Have done, several times... Acceleration graph a. release to somewhat over-g in approximately 1s. b. reduction in acceleration to approximately g over approximately 1.5s. c. reduction in acceleration to [<g] There is NO ~1.75s of ~FFA Velocity graph You don't give values for: a. ? b. ? c. ? Just: ~1.75s at ~FFA Same data - 2 entirely different results.
	Last edited by Christopher7; 2nd July 2012 at 01:49 AM.