2001-11-09 – Maths from the September 11th massacre

A Boeing 767-300 has a maximum takeoff mass of 156489 kg. It has a typical cruise speed of 489Kts = 251 m/s

Kinetic energy = 0.5*mass*velocity^2
giving 4,929,481,744 J or 4929 MJ from KE at cruise speed, max take-off weight.
This converts to 3,635,799,011 ft-lbs \”muzzle\” energy. (It should be noted that a \”crack\” was heard prior to impact, indicating that the aircraft had actually gone supersonic, and hence this figure is low.)

Factor in the nearly full fuel tanks…

For jet A-1 fuel, the net heat of combustion is min. 42.8 MJ/kg, and has a density of about 800 kg/m^3. (Density @ 15ÂșC, 775 to 840 kg/m3)
63,216 litres of AvGas weighs ~19,050Kg of fuel, max.
This converts to 815,340 MJoules from fuel.
This gives us a total of 820,269 MJ of energy, or 604,999 million ft-lbs.

For comparison:
Air-rifle 16.269816 joules = 12 foot-lbs
.22 long rifle rimfire (revolver/pistol) – 90 foot lbs
9 mm pistol – 340 foot lbs
.45 ACP pistol – 400 foot lbs
.357 Magnum revolver – 530 foot lbs
5.56 mm rifle (NATO calibre) – 1280 foot lbs
.303 rifle – 2,400 foot lbs
.338 Remington Ultra Mag, 4540 ft-lbs
High-powered 2 stage gas gun (up to 8,000 m/s at 20 grams) – 640,000 J or 472,039 ft-lbs.
US Army anti-tank round (19kg at Mach 5, 1658m/s)- 26,115 MJ or 19,261 million ft-lbs.
Boeing 767-300 – 3,635 million ft-lbs
Boeing 767-300 plus fuel – 604,999 million ft-lbs

Sources:

 

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