Was this ejected rock in a controlled demolition propelled by gravity or explosives?

The debris in that video was all accelerated by gravity. The explosions were not powerful enough, and ended several seconds before debris began to be ejected.

All the things that are supposed to be evidence of explosions are things that, in an actual controlled demolition, are NOT caused by explosions, but by the gravitational collapse following them.

Are you really postulating that the rock seen travelling at very high speed was ejected by gravitational forces and not by the explosives that caused that building to drop ?

That is not a very high building at all. Six stories. Around 80 feet high. Even the very top could only achieve a ground impact speed under total freefall acceleration of around 60mph. That rock is travelling at least that fast - probably faster.

And that is assuming that it was thrown outwards by the fastest part of that falling building. So an impact of maximum 60mph can cause a heavy object to hit the ground - then turn through 100 degrees to fly upwards in an arc, again strike the ground, not lose any momentum, but be observed still traveling at least 60mph as it leaves the frame ?

Seriously ? I would like to see an experiment where a rock that size is dropped from 80 feet and results in anything approaching that observed event. It was ejected by the explosives. Physics does not work to suit your own belief system.
So, to put forward a video of an explosive event to show that material can be thrown sideways is quite foolish. We know that. We know that explosives can throw things sideways.

Find me a verinage video where only gravitational forces are used to bring down a building without explosives - and similar things happen. Those planners know how to use Newtons Law's. They can use the well known kinetic equations and calculate how far material can be ejected, with the only force available being gravity, so that a safe cordon can be erected. CD companies using explosives must set that safe distance further away - because they know that the explosions can eject material- as seen.

Get back to me when you have dropped a few large rocks from 80 feet high and filmed one doing what we see on that video.
 
Note the timing, the rock did not leave the building at the time of the explosions, but at the time of collapse. Unless it was suddenly accelerated by an outside force just behind the tree line.

And there's videos IN THIS THREAD of objects being ejected sideways out of systems with vertical forces. Or does it have to be a rock now?
 
then turn through 100 degrees to fly upwards in an arc, again strike the ground, not lose any momentum, but be observed still traveling at least 60mph as it leaves the frame ?
Actually, I think you should go back and watch the video again. Go to the settings button and slow the video down to .25. Watch the rock come through the opening in the trees and hit the ground several meters in front of the guy wearing the red shirt. Then it bounces off the ground and gets deflected upward. Its hard to see at regular speed. So after reviewing this, we don't see the rock until after the building starts to collapse, so what @Hevach said is totally possible and honestly the best "assumption". The rock is moving an a downward angle through the trees that is consistent with the building's height. And how do you know the rock is moving at 60mph.
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Note the timing, the rock did not leave the building at the time of the explosions, but at the time of collapse. Unless it was suddenly accelerated by an outside force just behind the tree line.

And there's videos IN THIS THREAD of objects being ejected sideways out of systems with vertical forces. Or does it have to be a rock now?

Yes it has to be a rock in this particular discussion. Because that was put forward as an example to show that gravity alone can cause high speed ejections. I don't doubt that a downwards impact can result in a lateral move. I just doubt that the particular rock put forward as evidence does indeed show that. It seems much more likely that it was a result of violent explosions. Occam's razor at work.
 
Agreed. Explosives CAN eject material sideways at high velocity.

Thanks for proving that point very clearly.

The question is - Can gravity do that ?

Why do you presume that gravity was not a factor in what happened in that vid? I'd have to guess, but perhaps the total force of that building falling would exceed the energy contributed by the original explosions used to bring the building down. If you have ever split firewood you will know how easily vertical force can be converted to horizontal motion.
 
Because that was put forward as an example to show that gravity alone can cause high speed ejections. I don't doubt that a downwards impact can result in a lateral move.
Actually there is a really simple 1 minute video that shows how gravity alone without an explosion could cause lateral ejections;

This can be applied to any collapse (natural, demo, verinage). So long as there is resistance from below.
He also has a short 1 min video which easily explains the difference between static and dynamic loads.
 
Note the timing, the rock did not leave the building at the time of the explosions, but at the time of collapse. Unless it was suddenly accelerated by an outside force just behind the tree line.

And there's videos IN THIS THREAD of objects being ejected sideways out of systems with vertical forces. Or does it have to be a rock now?

I did observe the timings. Did you ? That rock cannot have left the site faster than 60mph if gravity did it because that is the fastest that even the top of the building could be travelling under freefall from that height. No object can strike another identical object, and impart a greater velocity on it, than it is itself travelling. Ergo - any struck object can only move at a max of 60mph in this situation.

So, to go along with your theory that rock simply had to have a maximum velocity of 60mph when it left. At 60mph that means the distance travelled per second is 29 yards. How far is it from the site to where the people are stood? Guestimate of 150 yards? Thats over 5 seconds at 29 yards per second. So the rock at 60mph would have had to have left BEFORE the explosion to travel that far. Conclusion :- the rock left the site faster than 60 mph. Not possible under your theory. Lets look for another explanation.

The video time shows the explosions at just after the 6 seconds mark. The rock then first appears through the trees at mark 9 seconds. Thats just under 3 seconds. It then strikes the ground in front of the people at the 10 second mark. Lets check the maths again. 150 yards overall in just under 4 seconds is around 90mph average.

Lets go back in time that 3 seconds when the rock is first observed and see whats was happening. Hmmm - thats when the explosions took place. Could it possibly be that the explosion launched that rock - which then travelled 100 yards in 3 seconds at 90 +mph to the tree line ? And then continued another 50 yards to hit the ground in front of the people in another second - or still at 90 +mph ?

You see - At risk of being accused of patronising - objects travelling towards you from a distance take longer to reach you than light does. You have assumed that the object left the site at the instant that you SAW the building debris hit the ground. To then travel 100 yards to the trees, inside a second, means that it would have to be moving at a very high velocity indeed. Over 200mph is the calculation.

Or perhaps it left before then, at explosion time, and travelled faster than 60mph which fits video times, observations, and the maths better. The weakpoint in your contention is that the max speed of the rock, under your theory, has to be around 60mph. But the video clock shows that it was going much faster - even starting the timing at the explosion. If you then compress the start time to when the building hit the ground, an average speed of over 200 mph would be needed to comply with the distance/time involved. How do you explain that when nothing in the building is moving faster than 60mph under gravity ? ( Except of course debris being thrown aside by the cutting charges )

Summary.

#1- If the rock left at the time of the impact of debris on the ground it would have to be travelling at a speed far in excess of what was possible under a gravity event in order to be observed in the timeframe recorded.

#2 - At the maximum speed possible from a gravity alone event it would have to have left before then - in fact before even the explosions are seen.

#3 - If the explosion caused the rock to begin its travels then it would be possible to agree with the speeds calculated from the video evidence. Average 90 + mph for 150 yards equals the time recorded from explosion to impact in front of the people.


Face it. That rock left as a result of an explosion.


And to addess your other point ; yes, it has to be a rock in this particular discussion. Because that was put forward as an example to show that gravity alone can cause large speed ejections. I don't doubt that a downwards impact can result in a lateral move. I just doubt that the particular rock put forward as evidence does indeed show that. It seems much more likely that it was a result of violent explosions. Occams razor at work. And maths seem to indicate that too.
 
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Yes it has to be a rock in this particular discussion. Because that was put forward as an example to show that gravity alone can cause high speed ejections. I don't doubt that a downwards impact can result in a lateral move. I just doubt that the particular rock put forward as evidence does indeed show that. It seems much more likely that it was a result of violent explosions. Occam's razor at work.

But we know that material can be ejected sideways from verinage collapses (although of course they take measure to minimize this).

And to be frank, it seems perfectly obviously that if a 1100 foot structure collapsed in a progressive manner, then there's going to be a lot of high energy impacts, and not all of them are going to be straight up and down. As demonstrated by my original Pen Drop video:



And this has ALL been covered in this thread already, multiple times, going back over two years.
 
Actually, I think you should go back and watch the video again. Go to the settings button and slow the video down to .25. Watch the rock come through the opening in the trees and hit the ground several meters in front of the guy wearing the red shirt. Then it bounces off the ground and gets deflected upward. Its hard to see at regular speed. So after reviewing this, we don't see the rock until after the building starts to collapse, so what @Hevach said is totally possible and honestly the best "assumption". The rock is moving an a downward angle through the trees that is consistent with the building's height. And how do you know the rock is moving at 60mph.

Much of your post has been answered in my reply to @Hevach. I think that he is wrong for many reasons.
 
And have a look at this again, a vastly lower energy collapse. No explosives. Skip to 1:30

Thanks but I know about Verinage. That material can be ejected from such a gravity event is well understood. My post was purely about a standard explosive CD event that was shown to us as some kind of evidence that lateral ejections can occur. Of course it can - even more so when explosives are involved. I just looked at the claim that the rock seen nearly killing a spectator was a result of gravity and not the explosions. My calcs seemed to indicate otherwise - thats all. To continue scratching at this particular nit would be off topic though.
 
So, to go along with your theory that rock simply had to have a maximum velocity of 60mph when it left. At 60mph that means the distance travelled per second is 29 yards. How far is it from the site to where the people are stood? Guestimate of 150 yards? Thats over 5 seconds at 29 yards per second. So the rock at 60mph would have had to have left BEFORE the explosion to travel that far. Conclusion :- the rock left the site faster than 60 mph. Not possible under your theory. Lets look for another explanation.
So you're guestimating your velocities and distances. How is that an inaccurate observation is going to give you an accurate measurement? How do you know the rock was moving at 60mph, and that the building fell at that speed. The downward velocity isn't constant, there's acceleration and deceleration.
Would you mind providing the math for your calculations?
 
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Thanks but I know about Verinage. That material can be ejected from such a gravity event is well understood. My post was purely about a standard explosive CD event that was shown to us as some kind of evidence that lateral ejections can occur.
How is gravity different in a CD vs a verinage collapse? Gravity acts the same way in both demo's. In a verinage we have the absence of explosives that yield lateral ejections. So lateral ejections are expected in all types of collapses demonstrated in this thread which means you don't need explosives to have lateral ejections, hence gravity and dynamic loads result in lateral ejections.
 
Thanks but I know about Verinage. That material can be ejected from such a gravity event is well understood. My post was purely about a standard explosive CD event that was shown to us as some kind of evidence that lateral ejections can occur. Of course it can - even more so when explosives are involved. I just looked at the claim that the rock seen nearly killing a spectator was a result of gravity and not the explosions. My calcs seemed to indicate otherwise - thats all. To continue scratching at this particular nit would be off topic though.

I don't think anyone suggests a demolition charge would be unable to throw a small rock some distance. The point of the thread is more that they would be unable to throw a girder a few hundred feet without throwing much smaller items all the way to the Bronx. (and especially without making any bangs)
 
No object can strike another identical object, and impart a greater velocity on it, than it is itself travelling. Ergo - any struck object can only move at a max of 60mph in this situation.

You contend that the collapsing building and the rock are "identical" objects??

Buh-bye....
 
An object very much can strike another object and impart a velocity greater than its own. An awful lot of our sports are based on that principle.

http://www.efastball.com/hitting/average-bat-speed-exit-speed-by-age-group/
This took me a while to find, but:

An average MLB fastball is 91 mph, dropping to 83 as it crosses the plate. It's met by a bat moving at an average of 85 mph, and then has its direction reversed and leaves at an average of 103 mph. That is a change in velocity of 188 mph imparted by an object moving at less than half that speed.

It's just a product of the mass and elasticity of the ball and the object you hit it with and the angle of the impact.

An object cannot impart more *energy* on impact than its own, but e=mv^2. A bat traveling 85 mph can transfer enough energy to a ball to give it a 188 mph delta-v and still have velocity left over.

A falling building has enough energy in it to accelerate that rock to relativistic velocities if you can Rube Goldberg an efficient enough means to transfer it all to such a tiny object.
 
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Then there's also a wide variety of situations where various forms of leverage and compression magnify the translated velocity.



On theory if you have a levered situation you can get hundreds of times faster velocity.

Or think about squeezing an orange pip between your fingers until it shoots out. Your fingers had zero velocity, just lots of force
 
I don't think anyone suggests a demolition charge would be unable to throw a small rock some distance. The point of the thread is more that they would be unable to throw a girder a few hundred feet without throwing much smaller items all the way to the Bronx. (and especially without making any bangs)

A demolition charge made with high explosives with the theoretical energy to propel a multi-ton girder hundreds of feet wouldn't leave it intact; it would shatter the girder into thousands of pieces. High explosives are terrible propellants due to their incredible power density.

If, for some reason, you wanted to propel a girder hundreds of feet you'd do much better with a massive charge of black powder, though Mr. David Chandler of AE911T says that he sees visual evidence of "nanothermite rockets" (I'm not making this up) being attached to some of the columns in the Twin Towers.
 
So you're guestimating your velocities and distances. How is that an inaccurate observation is going to give you an accurate measurement? How do you know the rock was moving at 60mph, and that the building fell at that speed. The downward velocity isn't constant, there's acceleration and deceleration.
Would you mind providing the math for your calculations?

I agree with you. Its nearly all estimation. I estimated the height of the building. I estimated the distance from the building to the treeline, and then the distance from there to the people. I also estimated the time for total fall at just over 3 seconds using the video as evidence.

I also agree that the rate of fall over time differs, and that it cannot possibly be entirely at the rate of freefall acceleration, as some resistance is being met.

What cannot vary is the rate of freefall acceleration which I took to be 32ft/sec/sec.

If you apply that to the kinetic equations and use an estimated 80 foot as the height, it gives a speed of 71.5mph as the final speed that an object such as a bowling ball, dropped in clear air, would strike the ground. Other equations work out at 2.23 seconds for that to occur.

You have already confirmed that you accept that the rate of acceleration cannot be true freefall at 32ft/sec/sec through the entire collapse. What about an estimation of 75% of 32ft/sec/sec to start with ? Thats an acceleration of 24 ft/sec/sec.

Using that acceleration and 80 feet drop gives us a final speed of 62 mph and a time of fall of 2.58 seconds. As observation shows a fall time of just over 3 seconds, rather than 2.58 seconds, we must conclude that it fell at less than 75% of freefall and reach a terminal velocity of less than 62 mph.

Of course you are allowed to make your own assumptions and estimates. Then apply the kinetic equations. The two variables are the height of the building and the time of fall from observation. When you have done that to your satisfaction please let me know the terminal velocity of the roofline of the building.

That will then be the maximum speed that an impacted piece of the same building can depart. My guestimate is around 60 mph.
 
. Or think about squeezing an orange pip between your fingers until it shoots out. Your fingers had zero velocity, just lots of force

I wondered when someone would suggest that the rock was in fact a large orange pip. And that two large pieces of stationary debris squeezed together with enormous force and caused that 'pip' to fly away.

I didn't expect it to be you Mick.
 
I also agree that the rate of fall over time differs, and that it cannot possibly be entirely at the rate of freefall acceleration, as some resistance is being met
I never said that, what I said was buildings don't collapse at a constant speed, there is a period of acceleration, and a period of deceleration. Whether or not a building reaches free fall velocities depends on the circumstances in it's collapse.
 
I wondered when someone would suggest that the rock was in fact a large orange pip. And that two large pieces of stationary debris squeezed together with enormous force and caused that 'pip' to fly away.

I didn't expect it to be you Mick.
But that is a thing that can happen is it not?
 
I think he meant identical in mass and size. Not that it was part of the building.

Perhaps. But that wouldnt make any difference. A huge chunk of masonary striking a small chunk of masonary at 60 mph would still only impart a max speed of 60 mph on the smaller piece. And that also emphasises the problem. Because to cause a rock to reach a speed of 60 mph the impacting piece would have to be at least the same mass. If the moving piece was much smaller than the piece it hits - then a far lower speed would be seen in the impacted piece.
Imagine that small rock at 60 mph hitting a massive chunk of many tons. The large mass wouldnt move very fast at all.

So my assumption of the rock having a speed of 60 mpg max was based on it being struck by a much larger piece of debris at that speed.
 
A huge chunk of masonary striking a small chunk of masonary at 60 mph would still only impart a max speed of 60 mph on the smaller piece.

If the two blocks were floating in space maybe.

But imagine an irregular piece of concrete on a flat surface, and you hit it with a hammer. The fragments of the shattered piece of concrete can go MUCH faster than the hammer.

Or, take a long slab of concrete, and bend it until it breaks (which you can do by having one end fixed, and dropping something on the other end). How fast do the fragments go?
 
That will then be the maximum speed that an impacted piece of the same building can depart. My guestimate is around 60 mph
The fact of the matter is no one is contending explosives couldn't propel a rock laterally or in any direction for that matter. You've acknowledged in a prior post that verinage demolitions could produce lateral ejections due to the force of gravity, here;
Thanks but I know about Verinage. That material can be ejected from such a gravity event is well understood.
So we all agree that the force of gravity could cause lateral ejections of material from a collapsing building. Similar to what happened in the WTC.
So then I asked you and I repeat;
How is gravity different in a CD vs a verinage collapse? Gravity acts the same way in both demo's. In a verinage we have the absence of explosives that yield lateral ejections. So lateral ejections are expected in all types of collapses demonstrated in this thread which means you don't need explosives to have lateral ejections, hence gravity and dynamic loads result in lateral ejections
There is countless evidence of demo's where we see the charges go off one by one with flashes (for exterior columns) followed by the blatantly loud explosive blast(s). The structure is usually standing with no exterior damage until the main shape charges go off, and then the building begins to collapse. When the building collapses we start to see debri and dust get pushed out and away from the collapse. This happens regardless of how the building comes down. So one would agree that regardless of whats used to bring a building down, we should expect lateral ejections from it. Hence you don't need explosives to propel beams, bone fragments, and office furniture laterally from a collapsing building, all you need is gravity and dynamic loads.
 
I never said that, what I said was buildings don't collapse at a constant speed, there is a period of acceleration, and a period of deceleration. Whether or not a building reaches free fall velocities depends on the circumstances in it's collapse.

A building can only achieve freefall acceleration if there is absolutely no resistance to its motion downwards. My paraphrasing of your words was meant to repeat what you had said. Your mixing of the words 'speed' and 'acceleration' causes confusion. My remark meant to imply that over the entire fall, the 'average' downwards acceleration would be less than true freefall. If I didnt make that clear I apologise.
 
Was that a serious comment ?
Yes.
I'm sorry, can the ejecta in the video not be accelerated sideways by hitting something below and being hit from the top at the right moment and angle?
It doesn't seem impossible.
Perhaps statistically unlikely, but so is a piece of ejecta almost hitting bystanders at a planned demolition.
 
@Hitstirrer, we seem to be drifting a bit off topic here. Do you have an example of some piece of ejecta from 9/11 that you think can only have been propelled out by explosives?
 
It doesn't seem impossible.
Perhaps statistically unlikely, but so is a piece of ejecta almost hitting bystanders at a planned demolition.
More like statistically very likely other wise buildings would fall straight down within their own footprint on every collapse. Instead we see dust and debris being forced out as the floors above collapse onto the floors below.
 
But imagine an irregular piece of concrete on a flat surface, and you hit it with a hammer. The fragments of the shattered piece of concrete can go MUCH faster than the hammer.

Or, take a long slab of concrete, and bend it until it breaks (which you can do by having one end fixed, and dropping something on the other end). How fast do the fragments go?

#1 Agreed.
#2 Agreed

But a chunk of masonary travelling at 60 mph ( hammer ) would struggle to cause just one fragment to fly 150 yards and then bounce onwards for another long distance. Just my opinion by the way.

Similarly, in my opinion, I find it hard to envisage a bending event to do the same thing.

Experimentation would be interesting. But I suspect that asking a serious laboratory to attempt to prove me wrong would be difficult. Even Myth Busters might apply Occam's razor and not pass the expence request.

Just my opinion.
 
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#1 Agreed.
#2 Agreed

But a chunk of masonary travelling at 60 mph ( hammer ) would struggle to cause just one fragment to fly 150 yards and then bounce onwards for another long distance. Just my opinion by the way.

Similarly, in my opinion, I find it hard to envisage a bending event to do the same thing.

Experimentation would be interesting. But I suspect that asking a serious labororatory to attempt to prove me wrong would be difficult. Even Myth Busters might apply Occam's razor and not pass the expence request.

Just my opinion.

What if the chunk traveling at 60 mph weighted 20 tons, and slammed into a vertical concrete wall, causing the wall to fail by bending?
 
@Hitstirrer, we seem to be drifting a bit off topic here. Do you have an example of some piece of ejecta from 9/11 that you think can only have been propelled out by explosives?

I said many posts earlier that it was veering off topic. But others seem to want to justify the initial claim - that the video posted showed that gravity was the cause of that dangerous event. I disagree.

But I also agree that this sideline should be discontinued.
 
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