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Structural Engineer On the Fallacies of Movie Bridge Destruction (hackaday.com)
szczys writes: Suspension bridges like the Golden Gate Bridge and the Brooklyn Bridge are favorite victims for movie makers but are almost always shown to perform in violation of the laws of physics. Structural Engineer Alex Weinberg couldn't stay silent any longer. He covers how bridge collapses in several major films should have looked. The biggest offender? Christopher Nolan's The Dark Knight Rises.
I stopped reading when he described a catenary as a parabola
http://mathyear2013.blogspot.c...
These main cables form a parabola
A cable hanging under its own weight forms a catenary, not a parabola. I presume that still applies when you hang a roadway from it.
You should have read further and into the comments as well. Catenary is indeed not a parabola, but the suspension cables are. The cables are not free-hanging, they carry a considerable mass, which makes them parabola-shaped. As soon as the bridge fails, the cables turn into catenary shape, which makes his usage of the words accurate.
Very fun movie to watch, but wow the bad physics. TFA mentions the Golden Gate Bridge standing in the background with the center span broken. Compared to all the other physics goofs, I didn't even notice that one.
- Oil tanker swung like a baseball bat (it would buckle and snap in half just lifting it by one end).
- Helicopters carrying gigantic armored robots (a C-5 Galaxy can carry a single M1A2 Abrams tank).
- EMP-type event not affecting one robot because it's nuclear powered.
- Nuclear reactor causing a nuclear explosion (they can't do that, their fuel isn't even the right type to attain uncontrolled criticality).
- Giant monsters with exoskeletons (they would collapse under own weight). I let this one pass because of the Godzilla tradition, including the streets and buildings.
Always happy to share our vast quantity of experiences.
Have gnu, will travel.
I'm with you on all of those.
For those that might be wondering about the oil tanker(and such). Consider how strong, proportionally, insects are compared to humans. This scaling continues. It's relatively easy to make a toy helicopter that can fall from several times it's height, ram it's blades into objects, and such and still come out without damage. A helicopter big enough for people? No way.
Things like oil tankers are carefully balanced and strong where they need to be strong for their designed purpose. A tanker is designed to carry it's weight while supported on all sides by water.
It's also why Superman's hands should tear through vehicles like paper instead of lifting them, much of the time. You don't jack up so much as 1/4 of a car without using specific points that are capable of holding the structure.
I don't read AC A human right
well.. in case of star trek and star wars.. there was explanations before for why tie fighters did not fight in atmosphere(they would break up) and why xwings had closing wings(closing or opening them while in space serves little purpose). also once upon a time star trek writers bothered to come up with plot lines where they didn't place the huge saucer space ship in atmosphere/gravity as well.
then came this one director who apparently was too stupid to understand backstories OR physics, so he made movies of both which seem just silly poorly informed fan flics. never mind the space phone.
the point is, that such things can destroy a plot. if there is a teleporter and flying to klingon home planet takes 1 hour and there is a space phone that can operate anywhere then everything else done in the movie is totally pointless.
with the batman, it doesn't really affect the plot how it looks when the bridge breaks - what matters for the plot is just that the bridge breaks. there's big plot holes around that sure about human behavior but that is hardly the point.
world was created 5 seconds before this post as it is.