You've made some incredibly stupid posts but this one ^ will be hard to top!<quoted text>The example of the car and semi represents the tower's construction. The lower beams were massive because they had to hold up a 60,000 ton building. The beams at the top was much lighter because it had much less weight to hold up. Hence since the North tower fell all the way into the basement, it was like a car crashing through a semi, which is impossible.
In the North tower... the 12 stories that came down, the most it could have destroyed would be another 12 stories, The falling part would have also been destroyed and the collapse would have stopped. A total collapse of the North Tower is the smoking gun. You don't need to be half smart to figure it out.
The example of the car and semi is utterly ridiculous for the reason Charlie already mentioned.
In your example the energy is determined by mass and velocity and the energy is used by the act of colliding. Once the collision is complete and the vehicles come to rest, no energy is available for further destruction.
And as Charlie stated, gravity is a decelerating force in your example.
In the case of a falling body, gravity is supplying the energy and it doesn't stop after collision.
What does "mgh" equal?
What does it represent?
Again, all the upper floors have to do for global collapse to progress is destroy the floor directly beneath it. That floor is now added to the mass and beholden to the same conditions,
If you were given a problem where the 2nd floor of a 13 story building failed would you assume the 1st floor withstood the forces being imparted on it?
Buildings are not trees and are therefor not homogenous, solid bodies where destruction can only be attained by destroying the whole of the material.
Buildings are made of assemblies attached together and those attachments are what fails when the forces are great enough.
Many papers have been written about exactly that subject, you obviously haven't read nor would you have a hope in understanding them.
The bottom line is that twoofer fiziks are a hilarious parody of real life and are a symptom of education systems that are hopelessly broken.
See Dr. Zorders, Insults are Easier, timesten...etc for further proof of the above statement.