This seems to be making the rounds on the net, including being posted by some who really should know better:
Yep, you know what they're trying to imply by this, and it is rather astonishingly dumb.
Well kids, to know why this implied comparison is nonsense, you have to recall that Newton's Second Law is F=ma. Force equals mass times acceleration.
There's a world of difference between a plane taxiing along at 5 mph hitting a pole, and that same size plane going 586 mph hitting a building. A very, very, substantial difference indeed.
That plane going 5mph hitting a pole is generating 90,030.7 pounds of force.
That same plane going 586 mph is generating 10,551,646.69 pounds of force.
That's a world of difference, as will be the result.
The second instance is going to cause a heckuva lot more damage than the other.
Don't believe me? Well, watch this YouTube video on the difference in damage that occurs as a car strikes an object at progressively higher speeds. Same objects, remarkably different levels of damage. Note that car never hit 400 mph, much less 500, and weighs a heckuva lot less than a passenger jet aircraft.
Still don't believe me? There's an experiment you can do all by yourself, but likely only once, and it's probably really not advisable to try.
Have someone throw an itty, bitty, little 115 gr 9mm bullet at your chest.
Doesn't do much does it? Bounces off, eh? Remember they claim those things can kill you.
Now, if you still think you know better, and wish to continue to ignore reality go ahead and have someone shoot you in the chest with it from a handgun.
I expect you'll have a different result, and note the size and weight of the bullet didn't change one bit.
Remember Newton's Laws are laws, not suggestions.
4 comments:
As somebody who used to use computers to model physical/mechanical systems, I would probably explain it from the standpoint of Conservation of Momentum.
A jet of water with no tensile strength at all will cut through steel or humans if it is going fast enough due to its momentum. Energy is not conserved but momentum is. If the water slows down then a portion of the target of equivalent mass must speed up even if it means separating from the host.
Consider a falling human body at terminal velocity (120mph to 180mph) hitting liquid water. The effect on the body is almost identical to hitting solid concrete. Conservation of momentum.
A plane hitting the curtain-wall of a modern building will cause the curtain-wall to implode inward while slightly slowing down the front sections of the aircraft causing it to crumple.
You don't have to believe me, but nobody in the structural modeling community sees any inconsistencies in the dynamics of the Twin Towers on 9/11/2001
The amount of stupid that came from some people (STILL !!!) from the planes hitting the towers.
https://twitter.com/nicksortor/status/1690829562718928897
Eaton Rapids Joe: Yep, conservation of momentum is a good way to explain it. As one of the many people that saw the second plane strike the WTC live on tv as it happened, I have little patience for stupid conspiracy theories. You're right that all the studies and models since confirm that it happened just as it did, with no need for any conspiracy nor value theories to the contrary.
Matthew W: Yep, the stupid is something else. Thanks for the link on the loss of the MiG.
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