The following is an excerpt from the "Gun P0rn" section of Castle Argghhh!
( http://www.thedonovan.com/archives/004010.html )
We know the formula for kinetic energy is KE = � mass x velocity2 . Now
let's check in with the Movie Physics Guys.
So in their example, a small .45 caliber bullet weighing 15 grams and
traveling at 288 meters per second yields is 619 joules of energy.
They further explain that if a man weighing 139 lbs (63.2 kg) were to fall
off of a bed, it would yield roughly the same energy as being shot by that
bullet; the difference being with a fall the energy is disbursed through
the entire surface area of the man's body versus a bullet where the focal
point is a tiny circle.
KE = �mass x velocity2
KE = (.015kg / 2) x (288 m/s x 288 m/s)
KE = 619 joules of energy
Potential energy is defined to be PE = (mass) x (g) x (height), where the
height is the vertical distance of the object from the ground and g stands
for gravitational acceleration or acceleration due to gravity. Near the
surface of the earth, g is a constant approximately equal to 9.8 meters per
second per second (m/s2). You can use these formulas to calculate the total
energy of the system by just adding up the forms.
PE = mass x gravity x height
PE = 63.2kg x 9.81 m/s x 1 meter
PE = 619 joules of energy
So taking this information, let's plug in the numbers of the Apache's M230
automatic gun ammunition. We have each 30mm round weighing 350 grams and
traveling at 800 meters per second.
KE = (.3505kg / 2) x (800 m/s x 800 m/s)
KE = .175 x 640,000
KE = 112,160 joules
Now that's a little hard to wrap your army around... I mean just how much
energy is 112,000 joules? Well, for starters it's 180 times the energy of
the .45 caliber handgun bullet. So imagine 180 people all pointing .45
caliber handguns at this guy's body and everyone pulling the trigger all at
the same time. Hmmm, yes...messy.
Furthermore, we can calculate just how high up this guy would have to
plunge in order to release the same amount of energy as was released when
he caught one of the Apache's 30mm rounds square in the chest...
112,160 = 63.2kg x 9.81 x height
height = 112,160 / (63.2 x 9.81)
height = 112,160 / 619.99
height = 180.9 meters (or 593 feet)
Now, taking our queue (sic) from the evolution of skyscrapers, I found an
average 4.26 meters (13.96 feet) per floor. Thus this terrorist you see
splattered all over Main Street in downtown Baghdad? He looks the same as
if someone tossed his happy ass off a 42 story building.
And the best part? The Apache's 30mm gun is really a popgun compared to the
30mm gun of an A-10 -- same diameter slugs but they're much heavier and
travel much faster. So should you be unlucky enough to eat one of the
Warthog's tank killing depleted uranium slugs...
KE = (.91kg / 2) x (1500 m/s x 1500 m/s) = 1,023,750 joules of smack down
1,023,750 joules / 619 joules per .45 cal bullet = 1,626 people shooting
you at once
1,023,750 joules = 63.2kg x 9.81 x height
height = 1,651 meters or 5,417 feet or a 1.02 mile freefall
But at a fire rate of 3,900 rounds per minute, the A-10's bullets will be
more like Lays potato chips -- nobody's gonna eat just one.
*************
Hmmm... An A-10's gun firing DU does a megajoule of damage... who needs
fricking lasers (with or without shark mountings)?
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