Common Sense

[defaultdotxbe]

Let's do a simple math problem... if the section above (upper mass of floors) came down at essentially freefall speeds, and the lower structure/floors were directly below this upper mass... how could the lower structure come down any slower than essential freefall...

once again 28th, an object in freefall is not at a constant velocity, it is under a constant ACCELERATION

verrrrry big difference there

 

[Mashuna]

Another simple question... so if the material from the collapsing floors was stacking - wherein increasing the size of the upper mass... what was this material made out of? We know that the large steel outer columns were being blown to bits... and lots of concrete was being smashed into dust... so what indestructible material was the floors made out of?

You know, if you didn't have so many people on ignore, you'd realise that all your questions have been answered about twenty pages ago. It would save the rest of us from having to re-read the same questions over and over. Give it a try.

For example, do you now understand how this works in real life:

Doesn't NIST say... the collapse increased in speed as it progressed downwards? Meaning the resistance from the lower floors didn't slow the momentum of the upper mass, but actually increased it.

Or are you still struggling to calculate how accelleration due to gravity works?

 

[pvt1863]

once again 28th, an object in freefall is not at a constant velocity, it is under a constant ACCELERATION

verrrrry big difference there

I sure am glad 28th wasn't in my dynamics class in college. I liked that professor too much.

 

[hellaeon]

28th just go do a physics course at school.

 

[28th Kingdom]

once again 28th, an object in freefall is not at a constant velocity, it is under a constant ACCELERATION

verrrrry big difference there

What are you saying... I mean just spit the 4473837 3838 out. NIST says the upper mass fell essentially at freefall speeds... are you saying the structure below the falling upper mass fell slower than the upper mass?

 

[beachnut]

I didn't say that... they're making this crap up.

What grade level did you leave school? Are you Charlie Sheen? You should have finished high school!

Erm, what? You are aware that objects ACCELERATE at 9.8m/s-2 due to gravity, aren't you?!?!

So... if we all agree that the lower structure (below impact floors) could have held the weight of the upper mass in a hypothetical situation where the impact floors were removed, and the upper mass was slowly lowered onto the lower floors/structure... than what we are saying is that the force from this weight (of the upper mass) falling 50-70 feet is what caused all of the lower floors to fail.

Now NIST...claims this force increased as the collapse progressed because the upper mass was increasing in size (presumably from the floors stacking in some capacity) so, my question is... when the upper floors fell down, and first made impact with the lower structure (below the impact floors) did those floors create any resistance... or do the laws of science not apply here? If they did absorb some of the energy released by the falling upper mass... than did the floors below this point, create any resistance to the upper mass that was hurling downward? And, if so... did they absorb any of the energy? Repeat scenario for remaining floors...

The point I am trying to make... is why doesn't the resistance from each floor... slow the movement of the upper mass... and if you say the mass was growing in size due to pancaking... than what happened to the core columns, since we have all seen that a pancaking of floors wouldn't have taken out the core columns.

http://www.youtube.com/watch?v=weqBynRZGG8

Bonus Video: http://youtube.com/watch?v=Awq6q5ZZUO4

Thanks.

Can you show us your calculations you removed? We could correct them for you.

Go to school. Come back in 4 years.

 

[beachnut]

What are you saying... I mean just spit the 4473837 3838 out. NIST says the upper mass fell essentially at freefall speeds... are you saying the structure below the falling upper mass fell slower than the upper mass?

What are you saying? Try to ask that again so even you can understand. Please

 

[defaultdotxbe]

What are you saying... I mean just spit the 4473837 3838 out. NIST says the upper mass fell essentially at freefall speeds... are you saying the structure below the falling upper mass fell slower than the upper mass?

to fall at essentially free fall speeds th eupper mass was accelerated at roughly 9.8 m/s^2

it then struck the lower mass, which provided resistance, slowing the acceleration to some value below 9.8 m/s^2, however, since acceleration was still positive, speed still increased (just at a slower rate)

im starting to think that not only do you not understand gravity, you dont understand the difference between velocity and acceleration

 

[pvt1863]

Talking with CTs reminds me of watching Star Trek. You can't help but believe that the writers have a mad lib program that allows them to just string unrelated scientific terms together in an effort to sound smart.

 

[Mashuna]

im starting to think that not only do you not understand gravity, you dont understand the difference between velocity and acceleration

I think he's already proven that he doesn't understand the difference. He won't admit it though - expect to see the same questions come back ten pages down the line.

 

[28th Kingdom]

once again 28th, an object in freefall is not at a constant velocity, it is under a constant ACCELERATION

No it's not... did you skip 6th grade science class?

The terminal velocity of an object falling towards the earth, in non-vacuum, is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and falls at constant speed.

http://en.wikipedia.org/wiki/Terminal_velocity

 

[defaultdotxbe]

No it's not... did you skip 6th grade science class?

The terminal velocity of an object falling towards the earth, in non-vacuum, is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and falls at constant speed.

http://en.wikipedia.org/wiki/Terminal_velocity

if you want to get technical, yes, but nothing on 9/11 fell long enough to reach terminal velocity so your point is moot

(oh, BTW, acceleration due to gravity is still constant even at terminal velocity, its just cancelled by resistance for a net acceleration of 0)

 

[beachnut]

Doesn't NIST say... the collapse increased in speed as it progressed downwards? Meaning the resistance from the lower floors didn't slow the momentum of the upper mass, but actually increased it.

Go to school and hurry back in a few years please!

Yes, it is called acceleration; gravity!

The momentum is not speed; momentum is conserved; the momentum relationship with the ever changing mass would modulate the velocity of each impact; but overall the growing mass did accelerate. (needs more work)

But 28th, you need some education.

 

[beachnut]

No it's not... did you skip 6th grade science class?

The terminal velocity of an object falling towards the earth, in non-vacuum, is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and falls at constant speed.

http://en.wikipedia.org/wiki/Terminal_velocity

oops, another F in physics!

 

[Anti-sophist]

No it's not... did you skip 6th grade science class?

The terminal velocity of an object falling towards the earth, in non-vacuum, is the speed at which the gravitational force pulling it downwards is equal and opposite to the atmospheric drag (also called air resistance) pushing it upwards. At this speed, the object ceases to accelerate downwards and falls at constant speed.

http://en.wikipedia.org/wiki/Terminal_velocity

Hi. Right. That's terminal velocity, which is completely and utterly irrelevant to freefall.

Try here: http://en.wikipedia.org/wiki/Free-fall

Free fall in its strictest sense is the condition of acceleration which is due only to gravity

 

[beachnut]

can so one explain why a human jumping from the WTC achieved terminal velocity but 40 tons of building did not!

explain mass to the young man who proves he flunked, or will soon flunk physics

 

[28th Kingdom]

to fall at essentially free fall speeds th eupper mass was accelerated at roughly 9.8 m/s^2

it then struck the lower mass, which provided resistance, slowing the acceleration to some value below 9.8 m/s^2, however, since acceleration was still positive, speed still increased (just at a slower rate)

im starting to think that not only do you not understand gravity, you dont understand the difference between velocity and acceleration

NIST says:

"Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos ..."

So while you claim... NIST is saying the upper mass feel through the impact floors at free fall... NIST is referring to the floors below i.e. lower structure - the level of collapse initiation i.e. impact floors - providing little resistance...wherein allowing the upper mass to fall at essential free fall.

 

[ConspiRaider]

Another simple question... so if the material from the collapsing floors was stacking - wherein increasing the size of the upper mass... what was this material made out of? We know that the large steel outer columns were being blown to bits... and lots of concrete was being smashed into dust... so what indestructible material was the floors made out of?

(bolding mine)

Didja ever go to Krogers or Piggly-Wiggly or really any grocery store here in the States and buy those store-brand frozen pizzas, like four of 'em for $9.99 or something?

You put one of these disc-shaped objects in the oven and then go away to finish up a chore or something - like, I dunno, straightening out the grass maybe - and you get engrossed and forget about the "pizza" in the oven.

You take that baby outta there and man - whatever they put in that crust just becomes indestructible when left baking for 45 minutes or so at 300 degrees Celsius.

Other than diamonds and zircons and the head of a certain unmentionable poster here at JREF with an astoundingly low IQ: That pizza crust is the hardest substance known to man. There's your flooring material, with no anchovies.

 

[Anti-sophist]

NIST says:

"Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos ..."

So while you claim... NIST is saying the upper mass feel through the impact floors at free fall... NIST is referring to the floors below i.e. lower structure - the level of collapse initiation i.e. impact floors - providing little resistance...wherein allowing the upper mass to fall at essential free fall.

That's largely correct. What you are saying, what NIST is daying, and what defaulttoxtube is saying are all largely the same. The fundamental difference is in the above post you are using words that you clearly do not fully understand.

When you try to take this knowledge and move it forward, your fundamental misunderstanding of the basic concepts makes you prone to serious error.

 

[28th Kingdom]

Hi. Right. That's terminal velocity, which is completely and utterly irrelevant to freefall.

Try here: http://en.wikipedia.org/wiki/Free-fall

Free fall in its strictest sense is the condition of accelerationwhich is due only to gravity

For example, the terminal velocity of a skydiver in a normal free-fall position with a closed parachute is about 195 km/h (120 mph or 54 m/s).

http://en.wikipedia.org/wiki/Terminal_velocity

Now you try HERE.