"Ejectile" is a shorthand combination of projectile
commonly used in physics
, especially physics where something's hit by something else and yet another thing (otherwise it'd be simpler to keep calling it the projectile) goes flying off. (or I suppose it could be used anyplace something's ejected ballistic
ally. So much for completely avoiding Freud
Ok, so that didn't make much sense.
To demonstrate the concept a little more competently, a concrete example is in order.
Let's let A(p,a)B be a
nuclear reaction. In order: A's a nucleus. It's just innocently sitting there, not unlike a deer in headlights
, when a beam
of p - which we'll suppose are protons
just to have something that actually begins with "p
" - comes flying in. Some of the proton
s get absorbed into the nucleus and knock off "a" particles - let's call them alpha
s. So the alpha particle
s go flying off, leaving behind a
somewhat modified nucleus which can no longer properly be called A
-- it's a different element, since the number of protons has changed. So let's call it B
Ok, now take a step back. What was the ejectile
here? The alpha
s. It couldn't have been anything else. A and B didn't move - at least no more than recoil made them, and they're probably big compared to the protons or alphas. (aka recoil
doesn't do much. like Earth
doesn't move much when you jump up and down.) And the proton
They were incoming, not ejected
- so they were the projectiles! Et voila
- process of elimination in action. Any process on any scale that is analogous to this one can be labeled similarly.
While I understand that this is probably way over-explained for most of you, it's a nice change from the level of the lecture I sat through this morning. Indulge me!