The Physics of 911

Now, how tall was the antenna?

You can tell me, I will believe you.

But I don't understand why you changed my answer of 5 to 6 seconds to 4.5 seconds? You told me to count the number of seconds, and I did as best as I could (given the smoke and the fact the antenna was tipping as it fell).

I played your game.... are you changing the rules on me?

I've watched it again, and I see five seconds.

But don't stop now. How tall was the antenna? I would assume that you knew this, based on your comment that the building did not accelerate, but descended at a constant rate.

I have no idea how tall the antenna is. I am going along with you, so you can tell me.

You are making a judgement call, and I was doing the same. I made the point earlier that this type of measurement is not possible to do in a scientifically valid way. I am playing along to see where your argument stops making sense.

It was 360 feet tall.

Here:

http://www.greenharbor.com/fffolder/speedtime.pdf

(Max does some more quick calculations).

So you are arguing based on your measurement of 4.5 seconds that the antenna should have falling 99.225 meters, but actually fell 109.7 meters (360 ft)? That doesn't make any sense, do you think it was being pulled downward?

I am pretty sure that your estimate is low (I just went back to reassure myself) especially given the fact that the antenna is tipping. Of course the smoke at the end of the interval makes an exact measurement quite impossible.

If the real number is 6 seconds, than the acceleration would be 6.10 m/s^2 indicating a significant upward force to counteract gravity.

As you can see, these estimates which are so hard to do precisely make a big difference.

I am playing along graciously. This is not a valid scientific exercise.

No, I am telling you that your idea that it was a constant rate of descent is totally wrong. In five seconds the antenna descended 360 feet. Now have a look at the graph here:

http://www.greenharbor.com/fffolder/speedtime.pdf

Do you recall saying this:

If there was no resistance, the antenna would be accelerating at 32 ft/second/second. If it is going at a constant speed, then it is being resisted. (If you don't believe this, just think about what happens when you drop something. It doesn't drop at constant speed).

It's late, so we'll pick up on this sometime later.

No Glenn, you have that completely wrong. The graph you picked is demonstrating something called "terminal velocity" which happens when an object is going fast enough that the force of air friction balances out the acceleration of gravity. This effect has nothing to do with the situation we are discussing here where the velocity is very low compared to the terminal velocity (the effect of air friction is negligible).

If you are going to start doing physics by google... you are going to quickly lose my interest. When people who turn to google to "prove" their point rather than to understand the science, they are showing that winning the argument is more important than being correct.

In science there are right answers and wrong answers. Your last post was simply wrong. The equation I gave you is the correct one.

It is THE explanation for what's going on in you head: you misunderstand physics and are ideologically bound to invent and project on any video of 911 all sorts of irregularities that nobody else can see.

I am seeing resistance. If the towers offered no resistance, they would have collapsed in a very different way, like a house of cards collapses. The entire building would have broken apart along its entire length all at once, because the structure would not be able to resist its own weight. That's not what I see. I see a progressive collapse that starts from the fire zone and slowly makes it way down. Therefore the structure is resisting.

This has nothing to do with what was observed. If you believe it does, then tell me how many seconds it takes for a falling object to reach terminal velocity.

Now let's get back to what was observed. Given that the antenna is 360 feet tall, and it took five seconds for its entire length to disappear below a marker, did the antenna remain at a constant speed drung its descent, or did it accelerate during its descent?

I didn't read all fourty-something pages so I apologise if this has already been tossed out there.

Science, physics, etc is all based off either theories that have been thoroughly tested or hypothesis that are generally founded in reality as we know it.

We (the collective we) have only had one instance in recorded history of passenger jets hitting buildings of this size and design. Unfortunately, this was not a controlled experiment so the unknown variables are countless. There are some known facts, but the variables are so vast that even with the known facts it still renders a hypothesis shakey at best.

For example. I could put an apple on my wife's head, walk fifteen paces, turn, and shoot it off with my crossbow. Now, I know (I hope) I'm going to hit the apple and the apple is going to explode, but to attempt to extrapolate what is going to go where is impossible.

You guys arguing about an antenna falling...We don't know what is going on there. Different pieces giving way at different times, the heat, wind, resistance, what kind of metal was it, what bolts, how was it welded, the angles, and on and on. There are so many things going on in the chaos of those buildings that even if you knew every single detail, it would still be impossible to sort out what should have been happening when.

From the outside looking in (on this discussion) you guys are right-fighting arguments about mysteries that will never be solved, that are impossible to solve. That is unless we start seeing a lot more buildings hit with planes, then we have a much larger problem to discuss.

You're comparing apples and antennas. Unlike the arrow, the antenna is a easily seen and measured as it descends. That is the issue at hand.

Do you have any real interest in the science, Glenn? Or are you just hacking around to make your political point. I could explain the science to you, there is a right answer. If we are just going to argue over made up science... that doesn't sound very interesting to me.

I already answered your question about the antenna in detail. I even did the math out for you to show you that it is likely that the antenna did show some resistance, but that from the video it is difficult to get an accurate measurement due to the fact the antenna is tipping and that it is obscured by smoke at the end of the interval in question.

If you are going to just make stuff up to support your political point, then there is no way to have a rational discussion.

You challenged me to analyze your video... and I did. It turns out that your video doesn't at all prove the point you are trying to make (and may even refute it). I did the measurement, and I applied the Physics, and it is what it is.

No you didn't.

You said: "If there was no resistance, the antenna would be accelerating at 32 ft/second/second. If it is going at a constant speed, then it is being resisted."

So I asked: Given that the antenna is 360 feet tall, and it took five seconds for its entire length to disappear below a base marker, did the antenna remain at a constant speed during its descent, or did it accelerate during its descent?

I'm waiting for your response.

That question can't be answered (nor is it relevant). If you want, I will explain the science. If you aren't really interested in the science, then please tell me not to bother since it will just be a waste of everyone's time.

The important equation is D = V0t + .5at^2. In this case I think we can assume that V0 (the initial velocity) is 0 so the only important part of the equation is D = .5at^2. This assumes constant acceleration.

It might be important that constant speed is works with this equation... it just means the acceleration is 0. Of course, in the real world the acceleration can change over the interval in question. There is no way to tell with this video whether this is happening, there is simply to many variables, plus the smoke, plus the tipping of the tower to make precise enough measurements.

If, as you originally claimed, the antenna was falling "with no resistance" (I am assuming this means free fall) than the acceleration would be constant with a value of 9.8 m/s^2 (or 32 ft/s^2).

It seems clear to me that this isn't the case. I don't know how much more detail you expect. We are analyzing a YouTube video (which is not a good way to make scientific measurements)... and this particular YouTube video is obscurred by smoke with a tower that isn't falling straight.

That being said... based on my measurement and my calculations, the tower was accelerating at a rate somewhat lower than 9.8 m/s^2. This would imply that the tower was not in free fall.

I have shown all my calculations in detail, that doesn't mean that the video is sufficient for anything more than rough estimates. You can't just make up science.

That being said, even the rough estimates I made seem to refute the claim you are making.

But... are you even interested in the science?

You said: "If there was no resistance, the antenna would be accelerating at 32 ft/second/second. If it is going at a constant speed, then it is being resisted."

So I asked: Given that the antenna is 360 feet tall, and it took five seconds for its entire length to disappear below a base marker, did the antenna remain at a constant speed during its descent, or did it accelerate during its descent?

It's an easy question to answer. Did the antenna remain at constant speed during descent or did it accelerate during descent?


Here is the video:
https://www.youtube.com/watch?v=xGAofwkAOlo
30 second mark.

You are suggesting that the visual evidence is insufficient to judge the rate of descent, and that we shouldn't believe our lying eyes. I disagree. There is no smoke obscuring the top of the building or the tip of the antenna.

Really Glennn. You are telling me that at 0:35 of that video you can see the top of the tower? I think you are just making stuff up to make your political point. Anyone can see the video for themselves.

The real question is whether you are actually interested in the science... or whether you are just interested in making your political point no matter what the scientific facts are.

You haven't answered that (or maybe you have).

The top of the tower is visible before collapse, allowing for us to create a base marker, and the tip of the antenna is clearly visible as it descends past that base marker. Look again.

But let's not lose sight of this:

You said: "If there was no resistance, the antenna would be accelerating at 32 ft/second/second. If it is going at a constant speed, then it is being resisted."

So I asked: "Given that the antenna is 360 feet tall, and it took five seconds for its entire length to disappear below a base marker, did the antenna remain at a constant speed during its descent, or did it accelerate during its descent?"

It's an easy question to answer. Did the antenna remain at constant speed during descent or did it accelerate during descent?

No, despite your suspicions to the contrary, I'm just asking you whether the antenna remained at a constant speed during descent, or whether it accelerated during its descent. So go ahead and answer the question.