Groups | Search | Server Info | Login | Register
Groups > sci.physics.relativity > #670487
| From | Thomas Heger <ttt_heg@web.de> |
|---|---|
| Newsgroups | sci.physics.relativity, sci.electronics.design |
| Subject | Re: energy and mass |
| Date | 2026-03-26 15:00 +0100 |
| Message-ID | <n2krurFbsl2U5@mid.individual.net> (permalink) |
| References | (22 earlier) <10pojcn$380fj$1@dont-email.me> <n2cavsFnf0rU4@mid.individual.net> <10pr8a3$1db2$5@dont-email.me> <n2hieiFi66uU4@mid.individual.net> <10q0fau$1r9os$4@dont-email.me> |
Cross-posted to 2 groups.
Am Mittwoch000025, 25.03.2026 um 12:01 schrieb Bill Sloman: > On 25/03/2026 6:59 pm, Thomas Heger wrote: >> Am Montag000023, 23.03.2026 um 12:31 schrieb Bill Sloman: >>> On 23/03/2026 7:21 pm, Thomas Heger wrote: >>>> Am Sonntag000022, 22.03.2026 um 12:21 schrieb Bill Sloman: >>>> >>>>>>>>>>>> the huge basement was not a compact mess of stone and steel, >>>>>>>>>>>> as we would expect, but was almost entirely undamaged. >>>>>>>>>>> >>>>>>>>>>> As you might expect if you neglected to think about what had >>>>>>>>>>> actually happened. >>>>>>>>>> >>>>>>>>>> No, not at all. >>>>>>>>>> >>>>>>>>>> I personally thought, that an exotic weapon was used, which >>>>>>>>>> could turn large structures of steel and concrete into fine dust. >>>>>>>>>> >>>>>>>>>> But I would have doubts about al-quida having such a device. >>>>>>>>> >>>>>>>>> Or anybody else. >>>>>>>>> >>>>>>>>>>>> That should shock you, since that would mean, that 80 to 90% >>>>>>>>>>>> of the original building materials vanished without a trace. >>>>>>>>>>> >>>>>>>>>>> Dust clouds are ephemeral. They blow away. They don't have to >>>>>>>>>>> blow far away to avoid showing up in the basement. >>>>>>>>>> >>>>>>>>>> Dust blows away, that's true. >>>>>>>>>> >>>>>>>>>> But how would you transform a 400m skyscraper into fine dust?? >>>> ... >>>>>>>>>> It also happened in mid-air, because the fine dust was blown >>>>>>>>>> away, before it had reached the ground. >>>>>>>>> >>>>>>>>> 400 meters is quite a long way up in the air, and a fierce fire >>>>>>>>> generates a lot of air-circulation. >>>>>>>> >>>>>>>> Well, yes 400m is quite a height. But free-falling rubble needs >>>>>>>> only a few seconds to pass that distance. >>>>> >>>>> 9.032 seconds. It gets up to a speed of 88.57m/sec. >>>> >>>> A little wind drag and we get 10 seconds for a piece of rubble to >>>> fall down from the roof. >>> >>> The bulk of the building was below the roof. >> Yes, that is actually a true statement and I have no intentions to >> reject you claim. >> >>>> The speed would also be very high and in the range of 300 km/h. >>> >>> Only if it fell all the way from the roof, and if it didn't slowed >>> down the air currents feeding oxygen into the fires and replacing the >>> hot air rising out of the fire. >> >> Sure, but if we take, say, only the highest 10% of the building and >> ignore the rest, then we would encounter at least those 10% smashing >> upon the ground level with more then 300 km/h. > > https://en.wikipedia.org/wiki/Collapse_of_the_World_Trade_Center > > says it didn't happen that way. When the floor slabs starting falling > onto the floor slabs below them, they stated from the top, and each > falling slab dissipated most of its kinetic energy in breaking the links > between the slab below it and the supporting columns. This only took > about a tenth of second for the lower floors, but none of them got to > travel at anything like 300km per hour. the supporting columns fell > sideways rather an straight down, and some of them j]hit adjacent > buildings. > >> This velocity would multiply with an enormous mass of up to 20000 kg >> per piece to a gigantic momentum. > > Except that it didn't. > >> And because momentum is a conserved quantity, we need tremendous >> amounts of material to stop such a falling piece. > > Momentum is only conserved from interaction to interaction. When a > building fall down over about an hour there are lots of interactions and > lots of accounting to be done. Sure, if a comet smashes onto, say, the Moon, then the large momentum of the comet falling onto the Moon needs to be stopped somehow by the surface, You could use several methods, but 'conservation of momentum' has advantages, because it would provide intuitive understanding for the formation of craters: The crater is so large, because the missing material inside the crater was needed, to balance the momentum of the moving debris. IoW: the material on the ground got struck by the falling part and unless the momentum is transferred to material from the ground, the falling piece would continue to move. That's why the velocity of the material from the ground could become very high and the crater very large, until finally the projectile is stopped. >> This material needs to shoot away from a large crater with very high >> speed. > > Only if it was travelling really fast when it hit the ground, and it > wasn't. Actually the velocity was more than 300 km/h and I would regard that as fast. We could also encounter 'elastic recoil', which could allow speeds of parts or the material on the ground to be faster than the falling debris. >> But that didn't happen, because the street level of WTC-Plaza wasn't >> demaged at all (well a few holes were actually punched into the street >> level, but not remotely as much and as large as expected). > > The WTC plaza wasn't actually directly below the Twin Towers. Well, possibly. I have never been there and don't know the exact street names. But you could gues what I meant: the surface of the ground level of the entire WTC-complex. >> So, material objects with a mass larger than 20 to of steel and >> concrete 'dustified' in mid air and were blown away. > > They got broken up in a series of smaller collisions, as each floor fell > onto the floor below it, and got further broken up by each impact in > succession. That's not how things fall, if they hit something hard below. If you would drop something breakable from some hight upon something breakable, but with high resistance against breaks, you would expect a different pattern: the upper part of a collision would cause breaks in the parts below, but also braks of the same kind in itself, because the both parts were assumed to have the same strength. If we concentrate on the upper part only (for a moment), we would expect parts of the falling piece to splinter off and fall partly outside of the former building shape, hence would fall in free fall outside down to the ground. Doesn't matter that much, what percentage would break of the upper part, because at least some parts would do that. But even at the hight of the actual impact zones, sections of the perimeter wall of the twintowers would fall down with enormous mass and velocity. IoW: possibly you were right and not that many 'cannon balls' or 'fright trains' would have hit the ground, but certainly some. But apparently this didn't happen, because every single of those sections of the perimeter walls would have pierced through the street level like a hot knife though butter. In this didn't happen, because the street level was mainly intact. You could easily see that, if you look at any pictures of the aftermath of 9/11, which show the remains of the twin-towers. E.g. you can see, if you look carefully, remains of fire-trucks and other cars in the rubble, which remained astonishingly undamaged. For instance some had still unbroken windows. This wouldn't be possible, if a just screw-driver would fall from that hight, let alone sections of the perimeter wall, weighing more then 20 tons. ... TH >
Back to sci.physics.relativity | Previous | Next — Previous in thread | Next in thread | Find similar
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-18 09:11 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-18 21:28 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-19 12:10 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-20 01:35 +1100
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-19 07:44 -0700
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-19 07:52 -0700
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-20 09:42 -0700
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-20 09:58 -0700
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-20 10:28 -0700
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-20 11:00 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-21 02:54 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-22 10:31 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-22 22:21 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-23 09:21 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-23 22:31 +1100
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-23 08:11 -0700
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-25 09:02 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-25 21:40 +1100
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-25 07:26 -0700
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-27 08:54 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-28 02:51 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-29 09:56 +0200
Re: energy and mass Daren Remond <ndno@dmrndd.us> - 2026-03-29 13:04 +0000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-30 08:33 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-30 01:32 +1100
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-29 07:39 -0700
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-30 08:48 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-30 18:15 +1100
Re: energy and mass Maciej Woźniak <mlwozniak@wp.pl> - 2026-03-30 10:17 +0200
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-31 09:13 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-31 22:46 +1100
Re: energy and mass Maciej Woźniak <mlwozniak@wp.pl> - 2026-03-31 13:57 +0200
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-25 08:59 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-25 22:01 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-26 15:00 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-27 02:47 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-27 09:13 +0100
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-28 03:17 +1100
Re: energy and mass Ross Finlayson <ross.a.finlayson@gmail.com> - 2026-03-27 10:39 -0700
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-29 10:19 +0200
Re: energy and mass Cloro Sandiford <iofnd@dosc.us> - 2026-03-29 13:01 +0000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-30 08:31 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-31 02:45 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-03-31 09:39 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-03-31 23:10 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-01 09:47 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-02 02:34 +1100
Re: energy and mass Maciej Woźniak <mlwozniak@wp.pl> - 2026-04-01 18:23 +0200
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-03 10:12 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-03 23:42 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-05 09:57 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-06 02:53 +1000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-06 13:09 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-07 04:11 +1000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-08 09:13 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-08 22:56 +1000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-03 10:31 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-04 03:16 +1100
Re: energy and mass The Starmaker <starmaker@ix.netcom.com> - 2026-04-03 09:38 -0700
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-04 04:15 +1100
Re: energy and mass The Starmaker <starmaker@ix.netcom.com> - 2026-04-03 23:18 -0700
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-04 21:37 +1100
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-05 10:14 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-05 20:58 +1000
Re: energy and mass Thomas Heger <ttt_heg@web.de> - 2026-04-06 12:51 +0200
Re: energy and mass Bill Sloman <bill.sloman@ieee.org> - 2026-04-07 04:27 +1000
Re: energy and mass The Starmaker <starmaker@ix.netcom.com> - 2026-03-19 11:17 -0700
csiph-web