brain sizes: Einstein's and women's
cary at afone.as.arizona.edu
Thu Sep 5 17:16:22 EST 2002
"Thalamus" <zhil at online.no> writes:
<Get this shit out of here (bionet.neuroscience) or you'll get tossed.
Brian! Yo, son, where ya been? Here I was, all cheerfully going
through your physics homework to find your mistake for you, and
when I turned around you had run off! An inadvertancy, I'm sure.
Here, let me get you back up to speed. No, I insist.
[ You had written:]
< It was like this, retard:
< F=m(v/t) - a=(v-v0)/t - a is acceleration,v is velocity, t is time, F is
< t=mv/F - exchanging t with F, see the likeness of the equations ??
< t=mv/ma - insert ma instead of F (F=ma)
< t=v/a - shorten the thing, by dispatching off with m (mass).
< t=(S/t)/a - here's the tricky part, insert S/t instead of v (S=vt or in my
< opinion v=S/t).
< t=(S/ta) - shorten the whole thing, so it is elegant.
< t²=(S/a) - transfer t to one side of the equation, and voila !!
< t=sqr(S/a) - you have Brian's equation of time, height and acceleration.
[ warmed by your enthusiasm for the topic, I responded:]
Yep, that's what you get, all right: Brian's equation. Unfortunately,
Mr. Newton's equation differs from yours by a factor of two, as I
originally pointed out.
[ we continue, in the same vein:]
< You loose, I win - as I am a Superior White God, and you're just a silly
< feminine creature :-)
Sorry, SWG, but this silly feminine creature realizes that
there's an implicit assumption of linearity in your step 5, where
you substitute S/t for v. That's true only for uniform velocity;
it's not true under acceleration, where velocity is constantly
increasing. In that case you can't do it (in a straightforward
manner) with algebra, you have to use calculus. In particular,
you have to integrate:
dS/dt = a*t, or
dS = integral (a*t*dt)
the solution to which is, of course, 1/2 at^2, not at^2. Which
is what I said originally. You fall a mile in 18 seconds, not
As I said to John, check any physics book. Or if you're just
too lazy, here's the first of a roughly a zillion hits on the net:
[ hey, T, looking through this, I find two mistakes on my part. The
first is a simple misprint; the second is a mistake or is not a mistake,
depending on the limits of integration. Let's have some fun, eh: see if
you can find them ]
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