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Q: Why does the can not fall off the brick before it explodes.
A:
1. Referring to Andrew's photo. We are
only seeing an instant just after the bullet has passed through the can,
therefore we don't know the velocity of the can (or how much kenitic energy has
been transferred to horizontal movement of the can), therefore we cannot say
whether or not the can will fall. I assume that it probably did.
2. That being said, if the can remains
on the brick, remember that the can has both inertia and also friction with
the brick. If the bullet moves fast enough and if the can and it's contents do
not slow the bullet enough, and if the inertia of the brick is high enough, and
if the friction between the can and the brick is high enough, the can will stay
on the brick, perhaps moved a little. This would be much like the magician's
trick wherein the magician pulls a table cloth out from under multiple table
place setting leaving the place settings essentially where they were, sans
tablecloth.
Q: In movie presentations of people or things being shot it seems that the
victim or target recoils from the initial impact - is this unscientific - or a
case of dramatic licence?
A: Primarily dramatic license. My experience (war) is that there is
sometimes noticable small recoil of the person being shot, sometimes it's
not noticable. Conservation of energy says there must be some recoile, just not
anywhere near as dramatic. Often movies depict a person shot at close range with
a shotgun being hurled back off his feet. Well, for every action there is an
equal and opposite reaction. If the energy was such that target recoiled in such
a fashion, the shooter would recoil even more so, as at least the target was hit
with shot that has lost energy by air resistance!
My experience with the movies is that none of these special
effects is true to real life experiencies or to conservation of energy or
to the laws of thermo dynamics. You would be bored, or at least less than
thrilled if it was. Keep in mind that the movies serve only two purposes -
make money and boost egos. This explaines a lot.
Regards, Bob... ----------------------------------------------------------------- Note: No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced. |
