Calculating Foot Pounds


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DMF38
December 10, 2006, 10:39 PM
Does anyone know how to calculate foot pounds of energy? Suppose I'm shooting a 250 grain bullet from .45 Colt, and the measured velocity is 800 fps -- how would I determine the foot pounds of energy produced?

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The Bushmaster
December 10, 2006, 10:46 PM
Bullet weight in grains X velocity squared divided by 450400 = ft lbs

Sylvan-Forge
December 10, 2006, 10:46 PM
bullet weight in grains x velocity squared
divided by 450400 = ft-lbs

edit: lol, The Bushmaster beat me to it

DMF38
December 10, 2006, 11:08 PM
Thanks for the help! :)

Clark
December 10, 2006, 11:31 PM
As every school boy knows, energy is equal to one half mass times velocity squared.

The trouble is, guns are in the wrong units.




Energy = .5mVV= one half mass velocity squared
E = .5 [250 grains] [800 fps] 800 fps]
E= .5 [250/7000 pounds] [800 fps] 800 fps]
E = .5 [.0357 pounds] [800 fps] 800 fps]
Mass = [wieght]/gravity= .0357 /32.2 feet per second squared = .001109 slugs of mass
Es=.5[.001109 slugs][800 fps] 800 fps]= 355 foot pounds of energy


Or you can just multiply grains times velocity times velocity divided by 45 and move the decimal place to what seems right.

3555555.556

Is a pistol 35, 355, or 3555 foot pounds?
It must be 355 foot pounds.

It does not matter, as Nicole Simpson took 5 foot pounds to the throat and dropped.

Jay29
December 11, 2006, 04:32 PM
Go here:

http://www.handloads.com/calc/quick.asp

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