/sci/ - Science & Math

we sagan/feynman thread now

So an electron walks into a bar... I forget the rest but your mother's a whore

>>5065240

>>4981824
>how can this be true when the deconstruction of the building(s) was faster than gravity?
It wasn't.

Each collapse can be broken down into four different "phases" during the collapse

Phase 1 - The initial collapse. Here only the damaged sections of the building are able to offer resistance. The acceleration of the collapsing mass is a little bit less than free-fall.
Phase 2 - The collapsing mass begins encountering undamaged floors. The rate of acceleration decreases.
Phase 3 - As the momentum of the collapsing mass and damage to the surviving support structure increases, the skeleton is able to offer less resistance. The acceleration of the collapsing mass increases, eventually approaching free fall.
Phase 4 - The collapsing mass begins to collide with the remaining floors and debris near ground level and decelerates.

At no point did the acceleration during any of these phases reach or exceed free fall, and we can easily calculate the average acceleration over the course of the collapse in both towers. The collapse of the North Tower took roughly 11 seconds, the South Tower about 9. The collapse of the North tower began at around 95rd floor (~355 m), the South tower at about the 80th (~300 m)

a = 2d/t^2

a(North) = 2(355 m)/(11 s)^2 = 5.87 m/s^2 = 0.60 G
a(South) = 2(300 m)/(9 s)^2 = 7.41 m^s^2 = 0.76 G


Physics: It's not just a good idea - IT'S THE LAW!

>>4966958
Fuck you. No, really, fuck you.

Unlikely. Most Asian languages (Mandarin, Hindi, Japanese, Korean, etc) have a large number of native speakers but are not widely spoken outside their country of origin. These languages will continue to be spoken in these regions but will not become significantly widespread. The same is true of many European languages (German and French for example are only spoken in their native lands and a handful of former colonies)

English is already the dominant language for business, literature, science, and telecommunication worldwide and will almost certainly continue to remain so. However, over the coming century it will probably simplify its spelling and grammatical rules - becoming easier to read, write, speak, and learn.

Spanish is also fairly widespread, as is Arabic, but neither of these will ever achieve more than regional dominance. As immigration from Spanish and Arabic speaking nations increases we may see pidgin dialects develop which combine elements of Arabic and Spanish with English become common in Europe and the Southwestern United States, respectively. These could eventually develop into full-fledged creole languages

That's my take on it anyways.

So you're thinking on a scale of about 100-150 meters? Well you wouldn't feel anything on the other side of the planet.

... closer to the impact site is another story.

The Barringer Crater in Arizona was likely the result of an impact with an object only about 50 meters across, and produced a crater roughly a kilometer across. A 150 meter impactor of similar density would create a crater 4-5 times that size and would probably be able to feel seismic effects a few hundred kilometers from the impact site.

Lots of local damage - could easily level a city - but no serious, global damage.

So you're thinking on a scale of about 100-150 meters? Well you wouldn't feel anything on the other side of the planet.

... closer to the impact site is another story.

The Barringer Crater in Arizona was likely the result of an impact with an object only about 50 meters across. A 200 meter impactor of similar density would create a crater 4-5 times that size and would probably be able to feel seismic effects a few hundred kilometers from the impact site.

Lots of local damage - could easily level a city - but no serious, global damage.

So you're thinking on a scale of about 150-200 meters? Well you wouldn't feel anything on the other side of the planet.

... closer to the impact site is another story.

The Barringer Crater in Arizona was likely the result of an impact with an object only about 50 meters across. A 200 meter impactor of similar density would create a crater 4-5 times that size and would probably be able to feel seismic effects a few hundred kilometers from the impact site.

Lots of local damage - could easily level a city - but no serious, global damage.