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Originally posted by Darkwing01
The acceleration of the body was 9.8m/s^2 in 1970, it was 9.8m/s^2 when it the planes hit. It was 9.8m/s^2 when the supports failed.
Originally posted by Darkwing01
I was 9.8m/s^2 when it fell one whole story. It was 9.8m/s^2 when it impacted the lower story. It was 9.8m/s^2 when the lower story failed.
Originally posted by Darkwing01
Do you see velocity anywhere in there? I sure don't.
You confuse deceleration with a lower acceleration.
There are 3 options. The acting force is larger than average resistance: acceleration. The acting force is equal to average resistance: constant speed. The acting force is smaller than average resistance: deceleration.
So what you need to show, using physics and math, is that the average resistance is equal or greater than the acting force. If it is not, there will be a net acceleration. So you need to know the resistance. This is very complex to determine. I have yet to see anyone make a realistic approximation. Obviously no truther has done so either. All we ever hear is baseless assertions based on general ignorance of physics.
Originally posted by DrinkYourDrug
Darkwing01 was correct in saying the plate would decelerate the brick as the brick broke the plate.
There is one option: the plate provides an equal and opposite force to the brick (the magnitude being the force required to break the plate).
I would agree that the design of the towers and (official) mode of collapse makes approximating the available resistance somewhat more complex, however in WTC7 it is a lot more straight forward.
Regardless of if you believe NIST's version of the internal structural collapse eight seconds prior, the building collapsed through its own columns (which we know should have been able to provide at least as great of a resistance force as they did when the structure was stationary). Instead they provided the resistance of wet cardboard.
Originally posted by Nonchalant
www.drjudywood.com...
Originally posted by Darkwing01
Force is MASS times ACCELERATION.
F=ma
Do you see kinetic energy or velocity in that calculation PLB, because I sure don't. Perhaps you should contact Newton and inform him of his error because WTC sure proved that velocity should be in there..... Or not....
The acceleration of the body was 9.8m/s^2 in 1970, it was 9.8m/s^2 when it the planes hit. It was 9.8m/s^2 when the supports failed. I was 9.8m/s^2 when it fell one whole story. It was 9.8m/s^2 when it impacted the lower story. It was 9.8m/s^2 when the lower story failed.
Do you see velocity anywhere in there? I sure don't.
The lower structure was resisting that mass at that acceleration, in fact was was capable of resisting twice to three times that. The only way that can overcome the resistance is by slowing the original mass down (decelerating it).
You can observe this in countless impacts and Verinage demolitions, to deny it is to deny reality.
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Take those concrete slabs you were talking about earlier, now take the broken slab and drop it the same distance on another concrete slab. Does it still break?
Can you see why it doesn't?
No he is not, it is one of the three possibilities. It depends on several factors such as how heavy the brick is, from which height it falls, how much resistance the plate is offering, etc.
Equal and opposite force doesn't say a thing about whether there is acceleration, deceleration or constant speed. Air molecules hitting your windshield also cause an equal opposite force on your car. Still the result can be acceleration, constant speed, or deceleration.
Is good that you ""know" that. I am awaiting your publication.
But 'a' is not the acceleration as result of gravity.
Originally posted by DrinkYourDrug
reply to post by -PLB-
No he is not, it is one of the three possibilities. It depends on several factors such as how heavy the brick is, from which height it falls, how much resistance the plate is offering, etc.
The scenario is that the plate could support the brick at rest but not when dropped from sufficient height. I stand by my post above.
The resistance provided by a fluid is not the same as inelastic collisions. This statement proves nothing.
If a plate can support a brick at rest it means the plate has a breaking strength which is greater than the weight of the brick. Therefore the brick will decelerate upon providing this equal and opposite force at the moment of impact because it has a net upwards force (its self weight downwards due to gravity countered by a greater than self weight force upwards provided by the plate).
Articles outlining very common and basic engineering knowledge are not usually accepted for publication.
If you assume that the plate completely fails at once, you are correct. Though the deceleration is a very short instance, the exact time between the brick hitting the plate, and the plate being broken. You probably wont even notice it when you look at it.
Originally posted by Darkwing01
The force exerted on the downward object is the force required to accelerate that object at 9.8m/s^2, and since the mass doesn't change the force doesn't change.
Originally posted by Darkwing01
You might not notice the deceleration, but you certainly would the change in velocity
Seriously, look at any number of collisions or Verinages...
Also I would like an answer as whether 1 pound of unconfined concrete dust would do the same amount of damage as one pound of solid concrete. Answers on the back of a postcard please.
This is wrong. An object falling 1 meter will have a much greater impact force than an object falling 10 meter
Originally posted by Darkwing01
reply to post by -PLB-
The impact force is the same PLB.
The MAXIMUM force that the top of the building can possibly exert on the lower structure is the force required to accelerate the body 9.8m/s^2.
Any deformation can only ever REDUCE that number by effectively reducing the amount of mass participating in the collision any given instant, but it will never increase it, because gravity stays the same and the mass is not increasing.
The force can never be anything other than mass times acceleration, velocity is not a term in the equation.
.
Actually, the mass of the collapsing floors are increasing, as each collapsed floor adds to the equation, minus whatever percentage is ejected.
The floors' masses don't just disappear.
Originally posted by Darkwing01
The impact force is the same PLB.
The MAXIMUM force that the top of the building can possibly exert on the lower structure is the force required to accelerate the body 9.8m/s^2.
Any deformation can only ever REDUCE that number by effectively reducing the amount of mass participating in the collision any given instant, but it will never increase it, because gravity stays the same and the mass is not increasing.
The force can never be anything other than mass times acceleration, velocity is not a term in the equation.
You refuse to look at an educational link I gave you.
Even though the application of conservation of energy to a falling object allows us to predict its impact velocity and kinetic energy, we cannot predict its impact force without knowing how far it travels after impact.
Note that the above calculation of impact force is accurate only if the height h includes the stopping distance, since the process of penetration is further decreasing its gravitational potential energy.
Originally posted by Darkwing01
Then the force exerted by an object travelling at one bazillion miles an hour is the same as the that same when it is stationary.