Open Letter to Dave Thomas

[ergo]

What force other than gravity, exactly, would be accelerating the ruler?

If I knew the answer, I wouldn't have asked the question.

Since leverage and torque were mentioned, I wondered if these might be additional forces acting in this situation.

 

[excaza]

You really need to learn basic physics. Like, really, really, really need to. Torque is not a force, it's the tendency for a force to rotate an object around its axis. You can't act on something with a force and a torque. Your force produces a torque.

Leverage isn't even a physics term. It's just what someone used because they noticed a longer lever arm allowed them to lift more weight. Because of a higher torque. But I'm not going to complicate things for you.

The only force acting in the video is gravity. That is, unless you believe there are magnets, springs, or maybe even tiny little rockets.

 

[T.A.M.]

If I knew the answer, I wouldn't have asked the question.

Since leverage and torque were mentioned, I wondered if these might be additional forces acting in this situation.

This is why most truthers just shouldn't comment on the collapses...at all.

He is right, go get some basic physics. Leverage can multiply or increase a force, it is not a force itself.

TAM

 

[W.D.Clinger]

Wouldn't this then technically be describing an additional force other than just gravity?

That's an interesting question, ergo.

I have two related questions for you. The first involves my driveway, which has a bit of a slope to it. When I place a tennis ball near the top of my driveway, it rolls down to the street.

How can that be? The force exerted by gravity is downward, but the street isn't immediately below the spot at which I place the ball; the street is some distance away, and that distance is more horizontal than vertical. Some horizontal force must be pushing the ball toward the street. Where did that horizontal force come from?

The second question involves a propeller beanie. When I push horizontally on one end of my hat's propeller, the opposite end of the propeller goes in entirely the opposite direction from the direction I'm pushing. How can that be?

It's almost as though a solid object reacts to force exerted on one part of the object by transmitting a force to other parts...but that would violate common sense. Must be magic.

 

[ergo]

I was perhaps picturing tension in the ruler, as if it was being slapped onto the surface, in which case, there would be some other force acting on it.

The final question I had about this example is that the ball is obviously falling from a higher elevation than the rest of the ruler, so could that, with air resistance, not account for why it hit the surface later?

I'm just skeptical of this "faster than g" claim, since the only other examples I can find involve other forces, like the Slinky example, where it can be said that the top is accelerating faster than free fall because of the spring action pulling it down.

 

[excaza]

I was perhaps picturing tension in the ruler, as if it was being slapped onto the surface, in which case, there would be some other force acting on it.

The final question I had about this example is that the ball is obviously falling from a higher elevation than the rest of the ruler, so could that, with air resistance, not account for why it hit the surface later?

I'm just skeptical of this "faster than g" claim, since the only other examples I can find involve other forces, like the Slinky example, where it can be said that the top is accelerating faster than free fall because of the spring action pulling it down.

You do realize Femr2 made you a gigantic picture?

And that the math supporting the faster than g acceleration has been linked twice?

And that if the end of the ruler and ball were accelerating at the same rate, the ball would never leave the tee?

 

[ergo]

And that if the end of the ruler and ball were accelerating at the same rate, the ball would never leave the tee?

That's better.

 

[DaveThomasNMSR]

...
I'm just skeptical of this "faster than g" claim, since the only other examples I can find involve other forces, like the Slinky example, where it can be said that the top is accelerating faster than free fall because of the spring action pulling it down.

No. The top of the Slinky could accelerate at g or more only if all 58 coils were suddenly cut, with Thermite-Triggered Super-Quiet Ultra-High EXplosives, a.k.a. Titty-Squex^TM, at exactly the precise same instant.

This Slinky clearly did not "collapse" naturally. There's no way to get around that. The Slinky was an Inside Job, plain and simple.

 

[Dave Rogers]

I was perhaps picturing tension in the ruler, as if it was being slapped onto the surface, in which case, there would be some other force acting on it.

Tension within the ruler is not an external force acting on the ruler.

There are two, and only two, external forces acting on the ruler. One is the downward force due to gravity. The other is the reaction force through the pivoted end, which is acting upwards. There is no downward force acting on the ruler other than gravity.

The final question I had about this example is that the ball is obviously falling from a higher elevation than the rest of the ruler, so could that, with air resistance, not account for why it hit the surface later?

The ball starts out in a cup, which will experience a greater air resistance and will move the air around it so that the ball isn't slowed by air resistance. We see the stick fall away from the ball, so it's nothing to do with the height they start at.

I'm just skeptical of this "faster than g" claim, since the only other examples I can find involve other forces, like the Slinky example, where it can be said that the top is accelerating faster than free fall because of the spring action pulling it down.

They, also, don't involve any other external forces, just forces internal to the falling object. WTC7, as a connected object, also had internal forces. That, in fact, is the whole point; it's the internal tensile and compressive forces within the object that can accelerate parts of it at a greater rate than g, although the external force can't accelerate the whole of it, on average, greater than g. Since the acceleration measurements we're discussing were only on a specific point on WTC7, not averages of the whole structure, it's quite possible for the same thing to have happened.

Dave

 

[Horatius]

Since the acceleration measurements we're discussing were only on a specific point on WTC7, not averages of the whole structure, it's quite possible for the same thing to have happened.

Dave

Which brings up an interesting question: all of the measurements I've seen have been of pixels at the roofline. How hard would it be to try such a measurement using pixles lower in the structure, perhaps an edge of a window, or something? Could we develop an acceleration profile for several points in the façade?

 

[cmatrix]

The bolded part confuses me. Are you saying that no matter how many structural engineers DO say it was a fire-initiated collapse, any who do so are in your mind not trustworthy, or are you saying that only only a few structural engineers think it was a fire-initiated collapse, and those are just the untrustworthy ones?

I think you need to keep in mind just how much you are in the abject minority, and how many structural engineers DO agree that damage and fires CAN explain the collapses. Does it make you sleep better at night to simply hand wave them all away as "untrustworthy"?

I'm saying any structural engineer that said WTC 7 was a fire-initiated collapse cannot be trusted. Unlike you, I am not swayed by the number of people that state something. Stating doesn't imply belief. Belief doesn't imply fact.

 

[cmatrix]

It developed a very noticeable lean to the south as it fell.

It sagged and fell straight down. At the end rolled to the south while staying in its footprint. Regardless of how it sagged and rolled it fell straight down into its footprint and this required extraordinary precision which is impossible from a fire-initiated collapse. Note that the sagging and rolling make the column failures immensely more precise than if the roof line stayed completely level during the entire collapse. Think what would be required to roll a building like that with explosives.

 

[cmatrix]

Pwned by Youtube:

You feel this video shows WTC 7 falling over sideways? I see a building falling straight down into its own footprint.

 

[cmatrix]

That whirring sound you can hear is Isaac Newton turning in his grave.

Dave

Care to explain your statement?

 

[Dave Rogers]

I'm saying any structural engineer that said WTC 7 was a fire-initiated collapse cannot be trusted.

Yep, standard faith-based reasoning - the trustworthiness of a source depends on whether it says what you want it to say.

Dave

 

[Dave Rogers]

Care to explain your statement?

I mean that your grasp of Newtonian physics appears virtually nonexistent.

Dave

 

[beachnut]

You feel this video shows WTC 7 falling over sideways? I see a building falling straight down into its own footprint.

You are too far away to see it leaning, not falling straight down. Even the roof is falling not straight; gee whiz, 6 to 8 seconds before the roof moves more than inches, the Penthouse fell through the WTC 7 structure, you can see deformations in the walls and interior collapse though the windows. Oops, not straight, very not straight.

How do you get silent explosives with no blast effects? Please be specific.

"Its own footprint" is a sign you don't understand the collapse, and proof you have no evidence for your claims. Evidence please of its own footprint? Is hitting the building across the road, its own footprint?

 

[twinstead]

Beachnut, cmatrix doesn't agree with you, so that means you can't be trusted

 

[cmatrix]

Please tell me you're not this clueless, while being this arrogant & insulting...

I just showed you something that you said was impossible: an object falling only under the influence of gravity, falling faster than G.

No other comment?

No, "whoops, perhaps my understanding of the situation was a little off. Maybe a little too simplistic"?



For once, you've said something right.

Yes, we are talking about a collapsing 47 story, massively interconnected steel structure. Not an isolated falling object.

For ALL falling objects (isolated or not)

Eqn 1: (F_g+ ΣF_i) / m = a

where:
F_g= force of gravity
ΣF_i= sum of all forces except gravity
m = mass of falling object
a = resultant acceleration of object.

For the special case of an "isolated falling object", by definition ΣF_i= 0. And the above equation reduces to:
Eqn 2: F_g / m = a = G
where G = gravitational acceleration (9.81 m/sec^2 or 32.2 ft/sec^2)

Note that, if ΣF_i≠ 0, then a ≠ G.

The balls & the coins are "isolated falling objects". They obey Eqn 2.

The cup & the end of the stick are not "isolated". They obey Eqn 1.

Now, let's see if you can take one, simple baby-step on your own …

Question 1: While it fell, was the north wall of WTC7 isolated from all other objects that might have imparted a force on it?

Question 2: Would it obey Eqn 1 or Eqn 2?

Question 3: Based on your answer to Question 2, is it possible for the north wall to fall at, or above, G?

Question 4: Using the variables shown in Eqn 1 above, describe how the north wall could fall "at G"?

Question 5: Describe how it could fall "faster than G"?



Yup.



The same clueless statements you bozos made about the WTC1 & 2 towers. Until others performed the same analyses that NIST did, and got the same results that NIST got.



You are making the same clueless error that some clueless "national security" bozo made when he declared the data "sensitive".

All the data is ALREADY OUT in the public domain. Dimensions, connections, assumptions, methodology, materials, material properties, etc. are all neatly tabulated in the NIST reports.

Anybody, who is not as clueless as you are, can recreate all that data easily.

This argument is simply the latest transparent smoke-screen, because all of your other transparent smoke-screens have evaporated. (Precisely why you bozos have abandoned WTC 1 & 2. All your "gotchas" have been answered.)



For someone who is totally clueless, you sure are arrogant.


tom

"I just showed you something that you said was impossible: an object falling only under the influence of gravity, falling faster than G."

What the hell are you talking about? I said no such thing. Please tell me you're not this clueless, while being this arrogant & insulting...

"All the data is ALREADY OUT in the public domain."

Really? So what was the FOIA request for? John Gross's phone number?

"Anybody, who is not as clueless as you are, can recreate all that data easily."

Well I certainly can't recreate it. But it sounds like you are saying it would be easy for you to recreate it. So let's see you do it. Unless you are completely full of crap, that is.

 

[carlitos]

You feel this video shows WTC 7 falling over sideways? I see a building falling straight down into its own footprint.

Just curious - if you were standing a couple of meters in front of the "footprint" of WTC7 while it fell (see the building falling down with the light blue line shown), do you think that you would be posting here today?