Does this material invalidate f=ma?
Nupe, no more than an ordinary cushion would.
Does this material invalidate f=ma?
It is the difference of someone hitting you with a 10 lb medicine ball at 5 feet per second, and a 240 grain bullet hitting you at 1,500 feet per second.
No, not really. f=ma Is there formula before impact.
The formula after impact is much more complicated. Some of the force is expended in
- the resistance and is reflected in the damage done to the bullet.
- the force required to harden the body armor
- the remaining force is expended over a larger area thus reducing the psi
I am sure someone with much more skills in applied physics would provide a better answer.
“Does this material invalidate f=ma?”
No, it can’t. What it apparently does is spread f over a large surface area very rapidly.
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It’s a non-Newtonian compound. The force is just spread out over a much larger surface.
Sorta, like water and corn starch- dip your finger into a thick slurry of it and nada, ram your finger in as hard as you can- solid as a rock....
Plenty of videos on the net.
I think F=ma is safe. It seems more that the F is spread out over a larger area and a significant portion of it is directed in a different direction.
No, the material goes through a temporary change of state analogous to liquid-solid fusion, which consumes the force analogue of the heat of fusion. Plus, it re-distributes localized force over a much larger area.
This new non-Newtonian material sounds like an improved version of "Sorbothane".
In my lab, I used to demonstrate "Sorbothane"'s effectiveness by putting my hand palm-down on a table, covering it with a 7/16" thick sheet of "Sorbothane" -- and then whacking on the sheet covering my hand with a big Crescent wrench until objects on the table bounced. It always horrified watchers -- yet, I hardly felt a thing...
This new "goo" should make a superb recoil pad for a shooting jacket or glove...