LNH: Legion of Net.Heroes Vol. 2 # 15: The Lost Issue! Three Exciting Stories!

martinphipps2 at yahoo.com martinphipps2 at yahoo.com
Sun Jun 11 03:18:36 PDT 2006


Tom Russell wrote:

> "A Lesson in Physics"
>
>    Adamant Authority-on-Everything passes by Obscure
> Trivia Lad.
>    "Adam," says Obscure Trivia Lad, "did you know that
> if you shrank to a height of six inches, your muscles
> would still apply the same amount of pressure as they
> do at normal height, precisely forty pounds?"

Physics Lad stepped forward to point out that pressure is measured in
pounds PER SQUARE INCH whereas a pound is a measure of weight (or, more
generally, force).

>    "Wait a second," says Adamant
> Authority-on-Everything.  "But you'd weigh less!
> There's no way you'd apply the same amount of
> pressure."
>    "It's a matter of mechanical force," explains
> Obscure Trivia Lad.  "Weight doesn't matter."
>    "Let's say there's an apple, it weighs five pounds.
>  Now, if you weigh five ounces, there's no way you're
> going to lift that apple."
>    "No," says Obscure Trivia Lad, "but if you applied
> pressure to it, it would have the same effect
> irregardless of weight."

Grammar Lad stepped forward to point out that "irregardless" is a
nonsensical word, even though many people use it, regardless.

>    "But it's bigger!  And your fist would be smaller.
> If you apply forty pounds across your smaller mass,
> there's no way you could even make a dent in it."
>    "But it's still the same amount of pressure," says
> Obscure Trivia Lad testily.  "Whether it's a fist or a
> wrecking ball, if it's applying forty pounds of
> pressure, the same amount of pressure is applied."
>    "You're telling me if you were six inches tall, you
> could still apply forty pounds of pressure to a
> ten-pound bowling ball, and that you could push that
> ball the same distance?"
>    "Yes, if you applied it to the correct place."

Physics Lad stepped forward to point out that if you were cut up into
tiny pieces then each piece would apply the same amount of pressure to
the floor but NOT the same amount of force, which is what is required
to move things.  (Actually, strictly speaking, this is assuming you
have been cut up while lying down.  You actually apply more pressure to
the floor when standing and even more when you are standing on tippy
toes.  As a person who has been cut up into tiny pieces cannot stand up
so the pressure exerted by each piece would actually be LESS than that
of a full sized person - inversely proportional to the area covered by
the body.  Loss of blood mass is another consideration.)

>    "Wait, wait, wait.  What does that mean, the
> correct place?"
>    "Obscure Trivia Lad means that if you place
> pressure to the center of the ball's surface, it will
> do a whole lot more than placing pressure to the
> tippy-top or bottom."

Physics Lad stepped forward to point out that this depends upon the
kind of surface on which the ball rests: on a slippery surface, you
want to push the ball and make it slide so you should apply force to
the centre of the ball but on a rough surface, you want to rotate the
ball and make it roll.  Now, at the tippy top, the distance to the
pivot point (ie point of contact with the surface) is doubled and,
hence, the torque is doubled and, hence, the speed is doubled.  This is
what car ads mean when they promise that the car supplies a lot of
torque.

Oh and, again, the word you want to use above is force, not pressure.

>    "But you're six inches tall."
>    "So you get a ladder."
>    "What?  No way, man.  You can't suddenly add a
> ladder."
>    "But..."
>    "You didn't say anything about no ladder," says
> Adamant Authority-on-Everything.
>    "But..."
>    "You said, and I quote, that no matter what your
> size, you could do the same amount of damage."

Again, no, if we cut you up into tiny pieces then each part of you
applies the same amount of pressure as before but the total force
exerted by your body weight is the same.  Unless, of course, by
"damage" you mean the fact that your blood will permanently stain the
carpet in which case, okay, fine.

>    "You're actually not quoting; you're paraphrasing."
>    "So now you're saying that you didn't say that."
>    "No.  Obscure Trivia Lad did say that, just not in
> those exact words."
>    "Well, you know what words you should have used?
> You should have said, if you're six inches tall and
> have a miniature ladder.  Which would actually make
> you over six inches tall, if you think about it."
>    "The pressure remains the same!" says Obscure
> Trivia Lad.  "The same!"
>    Adamant Authority-on-Everything sniffs.  "No, it
> doesn't.  You're only six inches, man.  You'd weigh
> less.  ... Hey, where are you going?"
>    "Obscure Trivia Lad is going to find a shrink-gun."
>    "Yeah?  Why's that?"
>    "So Obscure Trivia Lad can shrink himself."
>    "And why would you want to do that?"
>    "So Obscure Trivia Lad can punch you in the face."
>    "But you'd be teeny-tiny!" says Adamant
> Authority-on-Everything.  "There's no way your punches
> could even hurt me!"
>    "Then you have nothing to worry about," says
> Obscure Trivia Lad.

Now an even bigger question is "What happens to all the extra mass when
someone or something is shrunk down?  Where does it go?"  A real shrink
ray would simply make your molecules sit closer together so that while
your size would be the smaller, your MASS (and hence your weight) would
be alot more so your pressure on the floor would actually be a LOT more
(inversely proportional to the area covered by your feet).

>    "Obscure Trivia Lad will not be hurt," he says,
> sturdy and determined.  "Obscure Trivia Lad knows that
> the muscles in the arm apply forty pounds of pressure,
> irregardless of mass or weight!"

Search Lad notices that this is the first time the phrase "muscles in
the arm" have been used.  Physics Lad consults with Anatomy Lad who
wonders if a teeny-tiny arm wouldn't just simply break if it tried to
push anything.  After all, Neuton's Third Law points out that for every
action there is an equal reaction so the force/pressure exerted on the
ball would also be exerted back on that teen-tiny arm.  He points out
that this is why ants have exoskeletons.  Physics Lad decides to take
it as a given that the arm wouldn't break and then points out that the
independent variables that would determine how the ball moves are force
and torque and not pressure (which is measured in pounds per square
inch!).

>    "Obscure Trivia Lad is going to school you,
> junior," says the android almanac.  "No one can
> disregard the laws of physics."

Except the author. :)

>    Adamant Authority-on-Everything turns back just in
> time for Obscure Trivia Lad to break his nose and send
> him, arms flailing, hurtling to the ground.

A six inch Obscure Trivia Lad would have very tiny fists.  The pressure
exerted by the fists would be the same but the total force
(proportional to the area covered by the fist) would be minimal.
Therefore, Adamant Authority-on-Everything must be a wimp.

I must, of course, wonder how Obscure Trivia Lad must have fared, what
with being thrown backward by the reaction force of the punch.

Grades

Story... A
Grammar... B
Anatomy... C
Physics... F

Sorry. :)

Martin




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