C. Baize said:Didn't they also prove that bumblebees can't fly with physics, too?
Mathematical formulas are neat and look great on paper, but they don't ALWAYS transfer to real life circumstances.
yep they proved that a fixed wing aircraft with the wing surface area to mass ratio of a bumble bee could not fly... Note that a bumble bee is not a fixed wing aircraft and its wings do not produce lift by the same means as fixed wing aircraft. A fixed wing aircraft produces lift by creating a low pressure zone ontop of the wing, a bumblebee produces lift by creating vortices on the air and pushing those vortices downwards (IIRC). So the proof was inherently flawed.
In this case, the mathematical formula's DO directly translate into real world applications. Its called the law of conservation of momentum. Note that the impulse of a bullet impact with its target is going to be equal or less than the impulse generated between the shooter and the bullet. No one gets knocked down by shooting a 9mm, 5.56mm NATO, 12 gauge or 7.62mm NATO unless they hold the gun in a way that it can damage the shooter. Since the impulse will be equal or less (due to air friction) with the target, they are not going to be knocked down sans damage.