Quote:
Originally Posted by arizonaguide
To clarify further...in the definition of KE "Foot-Pound" is measured as the Energy required to raise a 1LB weight a vertical distance of 1FT. This makes no mention of Velocity units (only "distance")...yet velocity (including time units) is one of the variables in the KE formula.
(1/2Mass x Velocity^2 = FtLb.)
My "problem" Simply,
1.) if Kinetic Energy of the projectile is measured in FtLb,
and 2.) one of the KE formula's multipliers is "Velocity"...
then 3.) where the hell is the complete Velocity Unit (to include time) in the result?
Why do we throw away the TIME factor of velocity in the KE result?
Shouldn't the KE result be in FtLb/second rather than just FtLb? (as a full measure of the "capacity to do work")
If we're going to debate "stopping power" then lets talk about "power" being perhaps more accurate than "energy". I believe the KE formula itself is flawed in that it drops the unit of TIME from the velocity multiplier.
Someone REALLY smart PLEASE explain this to me.
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KE is the energy of a projectile in flight. That projectile’s ability to do work in the target is a different commodity: how that given KE is applied to a (living) target. Too many variables here (Time being one of them; geometry, target composition, projectile size and construction being others) for a handy, simplistic formula to hold sway: real world results are the preferred yardstick.
For myself, I try not to get carried away with the KE formula when considering ’stopping power,’ or a cartridge’s ability to perform in the real world. A few decades ago, we tended to confuse KE and Lethality, treating them as being synonymous. This notion led to a brief love affair with the 9mm Parabellum, which looks real good on paper when one is looking at KE numbers. Real world results did not align with the projections on paper, and the love affair ended badly in an FBI shootout in Florida on 11 April 1986.
With regards to Time, I suspect that this is what you’re looking for:
http://en.wikipedia.org/wiki/Impulse_(physics)
Put crudely, the Impulse deals with how quickly you lift that pound a distance of one foot.
DISCLAIMER: I do not fit this description:
Quote:
Originally Posted by arizonaguide
Someone REALLY smart PLEASE explain this to me.
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Where the heck is Team Sergeant?