T.R | Title | User | Personal Name | Date | Lines |
---|
571.1 | ans | WMOIS::B_REINKE | As true as water, as true as light | Fri Oct 14 1988 20:02 | 14 |
| Bill,
I can prove that the light goes out when the refrigerator door
closes. If I push in the button on the hinge side of the door
the light goes out. When I shut the door it compresses the
button. Therefore when the door is all the way shut and the
button compressed the light is out.
Bonnie
p.s. (actually if you close the door slowly you can see the light
is out before the door is all the way shut)
pps but this is still a cute idea for a topic!
|
571.2 | | ERIS::CALLAS | I saw Elvis kissing Santa Claus | Fri Oct 14 1988 21:35 | 3 |
| Well, ever notice that you never see baby squirrels or pigeons?
Jon
|
571.3 | What goes down must come up (hic!) | CAMONE::MAZUR | | Fri Oct 14 1988 21:46 | 20 |
| re: .1
A cute topic ?? Poor Bill may have been dead serious.
These little things in life bother some people ;-)
My question is:
When you drop something, does the object drop or does
everything else come up?
We all know what our common sense tells us but nobody has
been able to prove to me that this doesn't happen.
The universe is expanding. Everything is accelerating at
different rates depending its mass. I'm holding an apple and
let go of it. The rate at which the apple is accelerating
is much less than that of the earth ( and me too because the
earth is pushing at my feet ). Therefore, eventually the ground
will catch up to the apple and SPLATTT!!.
- Paul Mazur
|
571.4 | Making light of the situation | KAOFS::S_BROOK | Here today and here again tomorrow | Fri Oct 14 1988 21:49 | 20 |
| re .1
Sorry Bonnie, but just because you push the button and the light
goes out does it mean that when the door pushes the button that
the light goes out. Logic tells you it should, but you cannot
definitively say that it does - after all, there may be a sensor
that detects the metal of the door which keeps the light on !
Playing advocate to the devil,
Stuart
ps not all fridges shut the light off before the door is closed
... the switch trips on that last bit as the magnetic rubber pulls
the door to the box. Moreover there are some that use a metal
sensor to turn off the light.
pps This sounds like the magician responding to the heckler who
insists he had two birds, 200 scarves, a bunny, 10 decks of cards
and his beautiful assistant all hidden up his sleeves!
|
571.5 | Frames of reference, and "The Classic" | KAOFS::S_BROOK | Here today and here again tomorrow | Fri Oct 14 1988 21:56 | 18 |
| re .3
That's a matter of frames of reference ... and if you can define
the alternate frame of reference, then it's provable.
Take Centrifugal force, you know, the one that pulls an apple off
the end of a string when you spin it .... we think that the apple
is pulling on the string. The apple sees this as Centripedal force
that is that the string keeps pulling on it, pulling it off course.
------------------
Now for my favourite stumper ... the classic ...
There is a tree standing in the middle of a desert and no one around
for miles and miles. One day the tree falls down. Does the tree
falling down make a noise ?
|
571.6 | | ERIS::CALLAS | I saw Elvis kissing Santa Claus | Fri Oct 14 1988 22:00 | 7 |
| re .5:
My favorite version of that is:
If Helen Keller trips and falls in a forest, does she make a noise?
Jon
|
571.7 | TIMBER !!! | CAMONE::MAZUR | | Fri Oct 14 1988 22:04 | 11 |
| re: .5
That's an absurd question. First of all, deserts don't have trees
but I'm sure that you stated it that way to get the response you
are reading right now. Second and more important of all, trees
don't fall, the forest ( or desert ) floor comes crashing up
on the tree. ( see .3 )
OK, I'll stop with the reverse gravity stuff.
Paul Mazur
|
571.8 | �REBMIT | KAOFS::S_BROOK | Here today and here again tomorrow | Fri Oct 14 1988 22:25 | 33 |
| re .7
> That's an absurd question. First of all, deserts don't have trees
> but I'm sure that you stated it that way to get the response you
> are reading right now.
Please tell me what you would call those things that remain around an
oasis which has dried up ? Trees in a desert. Moreover, large cactii
(or cactuses if you prefer) could be called trees.
> Second and more important of all, trees
> don't fall, the forest ( or desert ) floor comes crashing up
> on the tree. ( see .3 )
Let's examine logistics here ... The ground cannot come crashing up
to meet the tree. The ground is already meeting the tree, at its stump.
Hence, and even therefore, the ground must perform a rotation at, or
about the stump. The tree must have sufficient rotational inertia
(more than the ground) to enable it to stay vertical during the rotation
thus meeting the ground after only 90 degree rotation. Unless, as I
mentioned before, you redefine your frame of reference, and can
sufficiently define the new physical properties in your new frame
of reference. Even then, only part of the tree sees the ground rushing
to hit it!
> OK, I'll stop with the reverse gravity stuff.
Good idea, 'cause I'll keep shooting it down as a frame of reference
problem.
Stuart -)
|
571.9 | what tree? | MINAR::BISHOP | | Fri Oct 14 1988 23:02 | 18 |
| re .5:
How do you know there's a tree in the desert at all? Don't you
see that the question itself _assumes_ that objects have existence
without observers?
If you can assume a tree exists when there is no one around to
see it, then it makes noise when it falls when no one is around
to hear it.
But if you believe that the tree makes no noise, how can you
believe that there is a tree (or a desert)?
Most such conumdrums rely on mixing models of the world in this
manner (e.g. the "Schoedinger's Cat" one mixes quantuum and non-
quantuum models of the world and achieves paradox).
-John Bishop
|
571.10 | Existentialism | KAOFS::S_BROOK | Here today and here again tomorrow | Fri Oct 14 1988 23:21 | 17 |
| I think the conundrum really is more simple than this ... it is
a matter of language usage and definition.
Let me put it this way, if there was an observer prior to the
tree falling over, and the same observer later sees what appears
to be the same tree prone on the ground, then it is safe to say
that it fell over. If it fell over, then by logical association
with tests where we examine other trees that fall over, then we
can all say that it must have produced sound waves, but the
question remains "Did it make a *Noise* ?"
The question is a matter of definition ... is Noise a definition
for sound waves, or is it for sound waves which are heard ?
Existentially I remain
stuart
|
571.11 | Strange, but true | CLT::LASHER | Working... | Sat Oct 15 1988 05:29 | 14 |
| Re: .2
"Well, ever notice that you never see baby squirrels or pigeons?"
Actually, this past summer, at my former apartment, I left a chair out
on the terrace too long and discovered a pigeon's nest, complete with
two pigeon eggs, just like in the SAVE brochure. I really wanted to
get rid of the damn things, but I was afraid of getting pigeon yolk on
the carpet, so I waited for them to hatch. Weeks went by, until
finally two cute little fluffy baby pigeons were hatched.
(Since you asked) I have, somewhere, pictures to prove it.
Lew Lasher
|
571.12 | A minor diversion | LAMHRA::WHORLOW | Living on a rope,tape & a prayer | Mon Oct 17 1988 01:36 | 26 |
| G'day,
reference the light in the fridge....
It seems I shall have to let you into a secret that I have known for
some time...
That button _actually_ rings a bell on the lounge room wall of the
man whose job it it to switch the light on and off. When the bell
rings, he nips over and turns the light on or off as required.
Sometimes, he goes on holiday and his nephew looks after the job
for him... you can tell when, for the light comes on a bit late.
(the nephew is a bit of a lazy soul and is not as good as the real
occupant of the job). The man in the fridge must exist 'cos how
often have you gone to the fridge for something only to find it
has been eaten, with no-one admitting to haven done the deed?
Derek
ps
Wilfred Pickles used, many year ago, to have a radio quiz show called
'Have a go'. A quetion he asked was "What is the last thing a lady
does before getting into bed?" Any answers?
|
571.13 | | TERZA::ZANE | foxglove employee | Mon Oct 17 1988 02:04 | 14 |
|
>"What is the last thing a lady does before getting into bed?"
Takes her feet off the floor?
----------------------------------------------------------------------------
The barber shaves everyone who does not shave himself. Who, then,
shaves the barber?
Terza
|
571.14 | Trees and deserts. | THEONE::PARSONS | So many notes, so little time..... | Mon Oct 17 1988 09:47 | 5 |
| We might not hear it, but we all know that damn tree has fallen
over in the desert, or rather the ground has rushed up to meet it,
for haven't we all felt the earth move occasionally ?
Regards..................Guy
|
571.15 | whodunnit ? | UNTADI::ODIJP | Elefanten springen nie | Mon Oct 17 1988 10:32 | 13 |
| Re .10
> Let me put it this way, if there was an observer prior to the
> tree falling over, and the same observer later sees what appears
> to be the same tree prone on the ground, then it is safe to say
> that it fell over. If it fell over, then by logical association
This does not take into account the man hiding *behind* the tree
with a power-saw when the observer was doing the observing .
Did it fall or was it 'pushed' ?
John J
|
571.16 | rubber dust | CIMNET::TABER | Under new management | Mon Oct 17 1988 13:53 | 14 |
| > This does not take into account the man hiding *behind* the tree
> with a power-saw when the observer was doing the observing .
>
> Did it fall or was it 'pushed' ?
More important -- did the saw make a noise when the observer couldn't
see it?
The old gag we used to wonder about was rubber dust. Every day, there
are millions (and billllllyons) of automobile tires gradually wearing
down. This has been going on for decades. So where's all the rubber
dust? It should be miles thick on the side of the road, but it's not
there...
>>>==>PStJTT
|
571.17 | Chewy chewy | CLOSET::T_PARMENTER | Tongue in cheek, fist in air! | Mon Oct 17 1988 14:57 | 5 |
| The rubber dust is consumed by rubber-eating bacteria. You can imagine
a "Cosmicomics" story in which the patriarch of the the rubber-eaters
has to hold his little band together for millions of years, promising
that things will get better, and then -- at last! -- tires and roads
and a rich, full life for the burgeoning race of rubber-eaters.
|
571.18 | A reply full of gravity | RDGENG::MACFADYEN | Roderick MacFadyen | Mon Oct 17 1988 16:20 | 21 |
| > < Note 571.3 by CAMONE::MAZUR >
-< What goes down must come up (hic!) >-
> Everything is accelerating at
> different rates depending its mass.
Come out of the dark ages please! It was to disprove this very
misconception that Galileo dropped a small cannonball and a large
cannonball simultaneously off the leaning tower of Pisa. Just to fill
you in on what happened, they hit the ground simultaneously, instead of
the big one first as you would seem to expect. The rate at which an
object falls in a gravitational field is independent of its mass.
If, when you let go of the apple, the ground leapt up to meet it,
then the ground, and you, and the whole Earth, would have to accelerate
to reach the apple. You would feel this acceleration when you let
go of the apple. Do you?
Rod
|
571.19 | Applesauce | CAM::MAZUR | | Mon Oct 17 1988 18:18 | 30 |
| > The rate at which an object falls in a gravitational field is
> independent of its mass.
Hmm, then why is it that when the astronauts were on moon
they only weighed 1/6th their earth weight.. Could it be because
the acceleration due to gravity on the moon is ~1.633 m/sec�
instead of 9.8 m/sec� on the earth ??
The point I was trying to make in note .3 was, how can we prove
that the acceleration due to gravity is down anmd not up.
> You would feel this acceleration when you let go of the apple. Do you?
Assume that everything is the way you think of things ( normal )
and you were a flea on the apple ( normal ?? :-) ) and somebody
dropped the apple. Would you feel a sudden acceleration ?? No,
you would feel weightless ( well relatively weightless because
there is a gravitational pull between the apple and yourself, the
flea ). Things don't suddenly accelerate, they just stop
accelerating. That is why when the apple is dropped, it stops
accelerating because it is not "attached" to the earth ( via the
hand via the feet on the ground ). It is then weightless until
the accelerating earth reaches the apple. Don't forget that
everything else is accelerating but their accelrations are
SO SMALL compared to the earth. Even if you take some of
Galileo's findings and say that all things in the earth's frame
of reference accelerate at the same rate with relation to the
earth, you still don't know what direction that acceleration is.
|
571.20 | Tides | VINO::JMUNZER | | Mon Oct 17 1988 22:42 | 4 |
| ...are caused when people at different places on the earth drop
apples into the water at approximately the same time.
John
|
571.21 | Apples and characters.. | AKOV12::MILLIOS | Mass.' 3 seasons: cold, -er, -est! | Tue Oct 18 1988 00:50 | 36 |
| If I drop an apple on this side of the world (Massachusetts, U.S.A.),
and since we know that for every action, there is an equal and opposite
reaction, does that mean that somewhere Down Under (or thereabouts),
an apple has flown up from the ground to strike somebody?
Wouldn't that set up a chain reaction, with the other apple coming
back down, and my apple coming back up to meet my hand?
Does this explain the "dead spots" on the court for the Celtics?
Every once in a while, they'll hit one (usually the opposing team
:^), and the ball will just not bounce... Perhaps one of those
aussies was sitting on the ball at that time, thereby deadening
the entire action/reaction chain?
I like the "rubber dust" problem...
And, Helen Keller would not fall in the forest. From her perspective,
the ground would come up to meet her. She also would not know if
she made any noise.
She also has no need for the little guy in the refrigerator.
A friend of mine used to teach a computer literacy class, and one
of his favorite questions (from a student to himself) was, "What's
a character?"
This caused much deep thought on his part. How to answer such a
basic question?
I told him he should have said that a character was the little guy
behind the screen, who was putting those letters up there. He's
quite a character, isn't he?
:^)
Bill
|
571.22 | Galileo made a mistake? | AKOV12::MILLIOS | Mass.' 3 seasons: cold, -er, -est! | Tue Oct 18 1988 00:52 | 8 |
|
Here's one...
If scientists can see from the earth an equal distance in all
directions, then for all practical purposes, are we not the center
of our universe?
Bill
|
571.23 | a hair raising experience... | COOKIE::DEVINE | Bob Devine, CXN | Tue Oct 18 1988 04:23 | 12 |
| re: .13:
> The barber shaves everyone who does not shave himself. Who, then,
> shaves the barber?
There are various answers to this conundrum.
1. She doesn't have to shave! (if the question is posed to ask
about the gender-neutral term of `barber'.)
2. A horrible childhood accident renders the male barber incapable
of growing facial hair.
3. A male barber doesn't shave; he uses Nair (or is that N'air?)
or depilation.
4. He just doesn't shave! Sort of like the cobbler's children?
|
571.24 | reflect on this! | COOKIE::DEVINE | Bob Devine, CXN | Tue Oct 18 1988 04:25 | 4 |
| Another stumper: What happens if two mirrors are carefully
aligned so that each reflects the other's reflection? Do
you get an infinitely reflecting light beam if a flash occurs
between the two?
|
571.25 | smaller and smaller, less and less | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Tue Oct 18 1988 07:07 | 11 |
| Re: .24
Yes, you do get an infinitely reflecting light beam. The images appear
smaller and smaller as the beam (or any image) travels further and
further. Also, the image gets dimmer and dimmer because each reflection
attenuates the light. Eventually, of course, quantum absorption of the
the last few photons makes the beam disappear entirely, so it doesn't
actually go on to infinity.
The problem with this topic is that DEC employs too many engineers. Any
conundrum has been heard and thought about by at least one of them.
|
571.26 | Expanding Earth | RDGENG::MACFADYEN | Roderick MacFadyen | Tue Oct 18 1988 10:58 | 13 |
| Re .19:
OK, let's assume that when you let go of the apple, the Earth jumps up
to meet it. Then, let's imagine stationing people holding apples at
places all round the globe, and let's arrange for them all to let go of
their apples at the same time. The Earth jumps up to meet all their
apples - so the Earth has become bigger, increasing in radius by
the height the apples were held above ground.
Is that a fair assumption?
Rod
|
571.27 | No surge here ! | CAM::MAZUR | | Tue Oct 18 1988 15:28 | 8 |
| re: .26
The earth doesn't JUMP up to meet the apples. It doesn't suddenly
accelerate when the apples are dropped. This acceleration is constant
( no surge ). Since everything has gravity and hence their own
constant acceleration, the expansion ( which is what the universe
is doing ) will not be noticed. Don't forget that the earth, you,
me and all our rulers and yardsticks will be expanding.
|
571.28 | | AKOV12::MILLIOS | Mass.' 3 seasons: cold, -er, -est! | Tue Oct 18 1988 17:16 | 14 |
|
re: .27
> ........ Since everything has gravity and hence their own
> constant acceleration, the expansion ( which is what the universe
> is doing ) will not be noticed. Don't forget that the earth, you,
> me and all our rulers and yardsticks will be expanding.
My mother swears she can tell that the yardsticks, measuring tapes,
and her are all expanding at different rates - every year, she's
shorter, a slightly different size, but weighs the same...
Maybe there's a mass correlation in there? :^)
Bill
|
571.29 | | ERIS::CALLAS | I saw Elvis kissing Santa Claus | Tue Oct 18 1988 19:09 | 5 |
| re the center of the universe:
Yes, we *are* at the center of the universe. But so is everyplace else.
Jon
|
571.30 | | TERZA::ZANE | foxglove employee | Tue Oct 18 1988 20:39 | 8 |
|
Isn't that like being on top of the world? The world is a sphere.
This means that anywhere I stand on the sphere, I'm on top of the
world.
Terza
|
571.31 | A new slant? | LAMHRA::WHORLOW | Prussiking up the rope of life! | Wed Oct 19 1988 01:31 | 18 |
| G'day,
An alternate solution to the expanding world from my science-literate
son who is studying Law and Economics at Uni....
The greater the gravity, the slower time runs.(hence time stops in a
black hole) Gravity's pull for a given body is constant. When we drop
an apple it falls at a constant rate, but because gravity is greater
nearer the earth than above it, the apple's time slows down so it
appears to fall further in the time span from where we watch it. ergo
it appears to accelerate.
Any comments? He says he has seen this in text books (both very
old and very new - does anyone have a reference?)
Derek
|
571.32 | Next Question? | DRUMS::FEHSKENS | | Wed Oct 19 1988 22:08 | 14 |
| Arghhhhh, this "discussion" about gravity reminds me of well justified
concerns about scientific illiteracy.
Anyway, I know the answer to the baby pigeon/squirrel problem.
It's the other side of the question of "where do the coat hangers
disappear to?". It's obvious that the coathangers disappear to
become reincarnated as full grown pigeons and squirrels.
I.e, coathangers *are* baby pigeons and squirrels. I mean, like,
you know, caterpillars don't look like butterflies and moths, so
why should coathangers look like pigeons and squirrels, right?
len.
|
571.33 | WARNING ! There are some of THOSE here | CAM::MAZUR | | Wed Oct 19 1988 23:01 | 11 |
| > Arghhhhh, this "discussion" about gravity reminds me of well justified
> concerns about scientific illiteracy.
I mean like OH MY GOD do you believe this is happening. I thought
scientifik iliteracy only happened in the inner city and underdeveloped
countries. It's happening right here in Digital. We wouldn't want
any non-Newtonian gravitational theories developed would we ?
Those geeky math dudes have had trouble( with a capital T ) in Center
City since the math illiterates came up with non-Euclidean geometry.
;-) ( as if it's needed )
|
571.34 | God's creation | TALLIS::ASHAH | | Wed Oct 19 1988 23:03 | 4 |
|
God is almighty, and can do anything and everything.
Can he create a stone that he himself can not lift ?
|
571.35 | A place for everything ... but not here please | KAOFS::S_BROOK | Here today and here again tomorrow | Wed Oct 19 1988 23:34 | 13 |
| re.34 You have just posed the stumper that has been responsible
for hundreds of years of arguments, wars and irrational discussions.
We may war here about whether globbedygook is English or whether
to boldly go forth is poor style and so on, but generally we agree,
or agree to differ. The world has historically been unable to do
either when it comes to discussions involving gods.
Can we please leave such discussions out of this notes file ?
Respectfully,
stuart
|
571.36 | | ERIS::CALLAS | I saw Elvis kissing Santa Claus | Thu Oct 20 1988 00:13 | 6 |
| re .34:
Interestingly enough, there's a discussion of this in
DSSDEV::PHILOSOPHY.
Jon
|
571.37 | | ERIS::CALLAS | I saw Elvis kissing Santa Claus | Thu Oct 20 1988 00:15 | 7 |
| re .32: (coat hangers)
Actually what happens is that lost paper clips mate and their offspring
are coat hangers. The coat hangers mature and beget bicycles, which in
turn have paper clips.
Jon
|
571.38 | bumper jacks | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Thu Oct 20 1988 04:41 | 10 |
| Bumper jacks!
Have you ever tried to find or buy a used one? They don't exist. No junk
yards have them in spite of all the junk cars, and we know each new car
started off with one.
I think what happens is that as each car finally dies, its bumper jack
also dies and is reincarnated. From the previous notes, it seems the
cycle must be: paper clips, coat hangers, bumper jacks, and finally
bicycles which have paper clips.
|
571.39 | rubber dust - whatsit dust! | LAMHRA::WHORLOW | Prussiking up the rope of life! | Thu Oct 20 1988 06:06 | 17 |
| G'day,
I've found it! (heard before somewhere?) _I_ know what happens
to tyre rubber.... It doesn't wear away! It doesn't become rubber
dust...
It gets pushed back into the tyre! When you go and buy a remould,
what they've _actually_ done is pull the tread back out again! That's
why its illegal to recut the tread - it messes up their rempuld
machines :-)
djw
ps I mean has anyone _actually_ weighed a used tyre compared with
when it was apparently new?
|
571.40 | Physicists do relatively well | VANISH::PRIESTLEY | Pigs Really Do Fly!! | Thu Oct 20 1988 15:05 | 33 |
| Re .lots about apples.
Where, Oh, where are all the Physicists? :-)
This little problem has a solution based on Newton's laws and a
bit of Relativity. If you sit in the frame of the earth the the
apple does indeed move towards the earth. If you sit in the frame
of the apple then the earth moves towards the apple and any other apple
falling at the same time will be seen to be moving towards the earth
and also moving relative to the apple you are in the frame of.
Another way of looking at it is to fix youself in the frame of the
earth then divorce yourself from it, so that as the frame moves
you remain where you are although (to forstall all those who will
say that the earth is moving anyway) you remain in on the same 'track'
that the earth is moving on without someone dropping an apple. It
will then be seen that the earth and apple move towards each other
a distance directly relative to the mass of each object. For instance
if you take two large, equal masses and bring them close to each
other and let go, the centre of mass of each object will move the
same distance towards each other until they touch. What happens
then depends on what the objects are made of, etc. If the mass of
the earth is 10 to the power 10 times the mass of the apple, then
the centre of the earth will be seen to move 10 to the power -10
times the distance the centre of the apple moves. This is why you
don't notice it, because the earth is a bit bigger than that :-)
If two people drop apples at the same time then the effects will
add up and even cancel out if the drops take place on opposite sides
of the planet. This is based on that age old law:
"Every action has an equal and opposite reaction"
Can we get onto something else now?
|
571.41 | Credit where due. | MINAR::BISHOP | | Thu Oct 20 1988 15:19 | 6 |
| The idea about paper clips pupating into hangers and so on
is from "Or All the Seas With Oysters", a short story published
in Fantasy and Science Fiction in the early fifties. I don't
remember the author off-hand.
-John Bishop
|
571.42 | Bird and cage problem anyone? | PRGMUM::FRIDAY | | Thu Oct 20 1988 15:53 | 19 |
| Does anyone know the answer to the bird and cage problem?
It goes like this.
Consider a bird that weighs X and a cage that weighs Y.
Assume that the cage is perfectly airtight and the bird is
at rest on a perch within the cage. Clearly the cage + bird
combination would weigh X + Y. What happens if the bird
starts flying around? Does the combination weigh X + Y or
just Y? Now assume the same masses, but the cage has a hole
large enough for the bird to fly in and out of. Why should
this make a difference or not?
Consider the follow variation on the problem. Suppose you have
a closed container with a small piece of ice inside it resting
on the bottom of the container. Will the combination weigh
less if the ice melts and turns to steam without escaping the
container?
|
571.43 | | KAOFS::S_BROOK | Here today and here again tomorrow | Thu Oct 20 1988 16:51 | 11 |
| re .42
Both problems are covered by basically the same answer.
In the case of the flying bird, as long as the bird is within
the cage, the mass of the bird produces a downward pressure via
its wings which is transmitted to the base of the cage so the
weight of cage + bird remains the same. I.e. instead of the birds
legs transferring this pressure when it is standing, it is air.
|
571.44 | Different density ... same mass ... same weight | KAOFS::S_BROOK | Here today and here again tomorrow | Thu Oct 20 1988 16:54 | 7 |
| re .42
Part 2
The same mass of material is in the container, whether it is ice,
water, or steam. The density is different, but the mass doesn't
change ... therefore the weight of the container does not change.
|
571.45 | I believe, but I'd sure like to see it | PRGMUM::FRIDAY | | Thu Oct 20 1988 18:22 | 16 |
| re .42 and .43
Has anyone actually tried it?
The bird example flies in the face of so-called
common sense. After all, why should it matter whether
the bird is flying around in an open cage or one that
is hermetically sealed? The second problem, which I agree
is fundamentally the same as the first one, would probably
be answered "correctly" based on common sense. Whereas
the same basic reasoning somehow seems inappropriate in the
first example.
My physics background tells me they're both the same problem
and I logically agree with .43's analysis, but I'd sure
like to have the comfort of actually seeing those expectations
verified by direct observation.
|
571.46 | Relatively simple? | ATLAST::DROWN | Goodbye 39 |:( | Thu Oct 20 1988 18:31 | 5 |
|
If I were piloting a space craft going exactly the speed of light,
and I flicked on the headlights, what would happen?
/sad
|
571.47 | Up Up and Aweigh | CAM::MAZUR | | Thu Oct 20 1988 19:56 | 11 |
| re: .42
The container with the vaporized ice will appear to weigh less
unless another constraint is put on the problem. The container
not only has to be air tight but it also must not expand or contract.
Also, the density of the air ( which is a function of temperature )
around this container will have an effect on the weight of the container.
I'm thinking of balloons. If you have two balloons with the same
amount of air in them but take up different volumes ( due to different
elasticity of the balloon or different temperatures ), the one that
displaces more air will appear to weigh less.
|
571.49 | Fizzix So Simple It's Wrong | DRUMS::FEHSKENS | | Thu Oct 20 1988 20:30 | 21 |
| re .41 - I believe "Or All the Seas with Oysters" is by Avram Davidson.
I think I've even got a copy of it buried in the unstructured mountain
range of books I euphemistically refer to as my "library". That's
probably where I acquired the notion (from the story, not my library).
re .46 - Much physical reality is counterintuitive. My favorite
example involves expectations of what happens when a walking person
drops a ball; what is the motion of the ball? Most people describe
it as falling straight down (i.e., hitting the ground directly beneath
the point where it was dropped), or being "left behind" (i.e., hitting
the ground *behind* (relative to the direction of walking) the point
where it was dropped), when in fact, the ball hits the ground *in
front of* the drop point, because it is carried forward with the
speed of the walk (ignoring the effects of air friction; this
"experiment" doesn't work terribly well with a feather). There
was an excellent (and disturbing) article in Scientific American
some time ago on this subject of "intuitive physics".
len.
|
571.50 | adding velocities | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Thu Oct 20 1988 20:35 | 30 |
| Re: .46
Who determines that your spaceship is going the speed of light? Since
that will never be true, the question's assumption is flawed, and the
question therefore has no answer.
Now, if you assume that the spaceship is going .99...9 times the speed
of light (towards the observer) and turns on the headlight, then there
is an answer. The observer will see the light from your headlight
arriving at exactly 1.0 times the speed of light but very strongly
shifted in frequency (color) toward the ultraviolet. You will see the
light from your headlight departing your spaceship at exactly 1.0 times
the speed of light and with a perfectly normal color. These experiments
have been done and the results verified many many times.
These results are counter to our everyday experience because we don't
experience velocities approaching the speed of light. For low speeds,
velocities add: if you shoot a rifle out the front of your car (say,
2000 feet/sec, I don't know how fast the things really go) while moving
55mph, then the bullet speed is 2000 ft/sec plus 55mph as measured by
the person standing on the road. That addition of velocities simply
doesn't work at light speeds. There is a formula, which I can't recall
instantly, for adding high velocities. The answer is always less than
the speed of light.
As a piece of trivia, the speed of light is exactly 299,792,458
meters/second. In 1983 the international standards committee redefined
the meter to be the distance light travels in one second divided by
that number. Unfortunately, I don't believe that's the correct answer
for Trivial Pursuit (tm).
|
571.51 | Everything's Relative | DRUMS::FEHSKENS | | Thu Oct 20 1988 20:48 | 8 |
| re .50 - This is just another example of how situational ethics
and cultural relativism have contributed to the downfall of traditional
American values. If it weren't for those danged pointy headed
liberal intellectuals, velocities would add up the intuitive way
they ought to!
len.
|
571.52 | quail at the thought | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Thu Oct 20 1988 20:53 | 1 |
| Right on! Vote for George Bush.
|
571.53 | weight is mass and acceleration due to gravy ! | KAOFS::S_BROOK | Here today and here again tomorrow | Fri Oct 21 1988 01:45 | 17 |
| re .-a few
I actually saw the flying bird test done on television, and the
bird wasn't even in a cage, it was in the open ... sure the weight
wasn't particularly stable as th ebird flapped it's wings but the
average was pretty much the same as with the bird sitting on the
disc it flew over. When the bird flew off the edge of the disc,
the weight dropped.
also re the ice ... the expansion of the container doesn't matter
the pressure expressed as weight / area may decrease, but the mass
and hence the weight doesn't change. The only thing that will affect
the weight is if steam / water / ice escapes the container, or,
the container contains is damaged, or the acceleration due to gravity
changes from its approx 32 ft /sec /sec
stuart
|
571.54 | Archimedes | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 02:45 | 8 |
| The expansion of the container does make a difference. The container is
buoyed up by an amount equal to the weight of the fluid it displaces.
This isn't particularly significant with ice expanding in air because
the weight of the air displaced is small compared to the weight of the
expanding ice. It is significant for hot-air balloons. And it is
significant for making ice float.
If it's good enough for Archimedes then it's good enough for me.
|
571.55 | tide's in; tide's out | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 02:54 | 9 |
| Some more:
1. Consider an ice cube floating in a glass of water. What happens to
the level of the water as the ice cube melts?
2. Consider a ship in a closed lock of the Panama Canal. The bosun
throws a life jacket into the water; what happens to the water level in
the lock? What happens to the level when the bosun lowers the anchor to
the bottom?
|
571.56 | Tennis anyone? | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 02:56 | 2 |
| Sixty-nine people have entered a single-elimination tennis match. How
many matches does it take to determine the winner?
|
571.57 | Davy Jones's Locker | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 03:04 | 3 |
| There is an old seafaring myth about Davy Jones's Locker. Supposedly
sunken ships don't go all the way to the bottom but rather "float" part
way down. Is this possible? Why or why not?
|
571.58 | match , make me a match - ok me and tarzan, you and jane | LAMHRA::WHORLOW | Prussiking up the rope of life! | Fri Oct 21 1988 07:26 | 16 |
| G'day
spoiler follows for -.2 the tennis games...
Generally, for a singles match you need two people :-)
One must be a loser. So every match has one and only one loser. If N
people take part, n-1 must lose. - there is one and only one final
winner. Therefor for n-1 losers, there are n-1 matches.
For 69 competitors there must be 68 matches.
derek
|
571.59 | the ball was on the loin ! | UNTADI::ODIJP | Elefanten springen nie | Fri Oct 21 1988 10:44 | 7 |
|
Re .58
Mafferma'ickly correct . However , if the eventual winner is McEnroe
then the audience has lost aswell .
John J
|
571.60 | I must have been watching "Cheers" instead of CNN | CIMNET::TABER | Under new management | Fri Oct 21 1988 15:41 | 10 |
| > Now, if you assume that the spaceship is going .99...9 times the speed
> of light (towards the observer) and turns on the headlight, then there
> is an answer. ...
> These experiments
> have been done and the results verified many many times.
Oh boy! Fill in the details for me... I missed the news report of the
headlight-bearing spaceship that does .99...9 the speed of light. Does
it use solid fuel boosters?
>>>==>PStJTT
|
571.61 | | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 16:35 | 1 |
| The National Enquirer article didn't say what type of booster was used.
|
571.62 | What happens if you throw in Noriega? | PRGMUM::FRIDAY | | Fri Oct 21 1988 20:24 | 19 |
| re .55
When the anchor is lowered to the bottom the water level in
the canal should go down. When the anchor is in the boat
the boat displaces enough water needed to float the entire
anchor. But, the anchor is more dense than the water and
occupies a fixed volume which is smaller than the amount
of water that needs to be displaced to float it.
In the case of the life jacket, the water level should stay
the same. When it's in the water it will displace only
enough water needed to float it, which will be the same
amount as if it's in the boat.
In the case of the ice cube the level will also be unchanged
when the ice melts. That's because water becomes more dense
as the ice freezes, and the corresponding change in volume
will be exactly equivalent to the volume of ice above the
surface of the water.
|
571.63 | Noreiga | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Fri Oct 21 1988 21:57 | 3 |
| If you throw Noriega out of the boat into the lock, the water level
stays the same as long as he floats. When he exhales and sinks, then
the water level goes down.
|
571.64 | | VISA::MONAHAN | humanity is a trojan horse | Mon Oct 24 1988 21:23 | 13 |
| I want to know what happens to car radios. It seems that most
cars these days come equipped with car radios, everyone has had
at least one stolen, and replaced it with a new one. Some people
take their car radio out when they scrap a car, since the things
do not wear out now they don't use valves (vacuum tubes) any more.
Logically, there must be many more car radios than cars
by now.
Is there some elephants' graveyard of car radios somewhere?
Is someone equipping Eskimo sleds with stolen car radios? Do they
metamorphose into those peculiar metal shapes you find in your toolbox
and can't imagine what they might fit?
|
571.65 | | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Mon Oct 24 1988 22:25 | 2 |
| And car bumper jacks. Where do they go when cars die? You can't find
them at junk yards.
|
571.66 | I think you've got some unstated assumptions | NIMOY::TABER | Answer hazy -- ask again later | Tue Oct 25 1988 12:52 | 12 |
| > I want to know what happens to car radios.
You must drive a BMW.
> It seems that most
> cars these days come equipped with car radios, everyone has had
> at least one stolen, ...
You must certainly drive a BMW. Nobody has ever shown an interest in
stealing my stock GMC radio. I even park in the city with the doors
unlocked and the windows down...
>>>==>PStJTT
|
571.67 | Like a bad penny... | MISFIT::GEMMEL | and now here's Mac and Tosh... | Tue Oct 25 1988 14:39 | 14 |
| Actually, a large number of radios end up in my garage. I have
six old Volvo radios (the pre-240 series kind, AM only) which are
being put back together to create oNe WorKinG (opps, I've got
a volume problem in that one) unit.
Another theory is that there is a massive circular shift going on
with all the radios, bumper jacks, spare tires, and Cadillac hood
orniments. The reduction of units which allows for infux of "new"
models is performed by Munchkins who rebuild the old units into
the radios, etc, for the "new" cars which are really old beer cans
reformed into body panels.
--- Nothing is new, it's the same old *stuff* in a new wraper ---
|
571.68 | Diffusion theory of auto parts | PRGMUM::FRIDAY | | Wed Oct 26 1988 15:17 | 29 |
| There's also the diffusion theory of distribution for
old radios, bumper jacks, etc. In diffusion theory things
flow from areas of high concentration to areas of lower
concentration. Munchkins who remove radios, spare tires,
and so on from new cars are not really acting independentally.
Typically they live on the boundaries of areas having radically
different concentrations of these items, and so experience the
stresses created by the differences of concentration. Their
actions serve to equalize these pressures.
The author of .66 is apparently living in an area of high
concentration, far removed from any area of low concentration.
Such stagnation is, of course, to be expected.
Collectors of used radios, etc illustrate diffusion theory's
clustering effect, in which like particles tend to remain
together and produce micro-areas of high concentration, even
in the midst of areas of low concentration. Some physicists
believe that clustering is futher explained by gravitational
theory, in which particles start attracting when they come
close enough to come under the influence of their own gravitational
fields.
Interestingly enough diffusion theory supports a recursion
principle, which states that particles will break down into their
constituents to remove low concentrations of them, even in the
environment of high concentrations of the original particles.
This explains the observed "beer can <> body panel" equilibrium
quite nicely.
|
571.69 | But I left it just there! | AYOV27::ISMITH | Considering a move to Memphis | Mon Oct 31 1988 12:24 | 10 |
| Imagine the scene. You are working in your laboratory in the cellar
of your unassuming little semi in Chateau Au Lait (Castlemilk).
Suddenly, you make the breakthrough you have been waiting for. You
have discovered the Universal Solvent!!
So what do you keep it in?
Ian.
|
571.70 | Immutable Container | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Mon Oct 31 1988 13:26 | 3 |
| You keep it in the Immutable Container, of course.
Or you suspend it with high-power sound waves.
|
571.71 | Who's number 2? | COOKIE::DEVINE | Bob Devine, CXN | Mon Oct 31 1988 17:57 | 2 |
|
Why are *all* football teams #1? After all, their fans say so...
|
571.72 | SPLAT! | COOKIE::DEVINE | Bob Devine, CXN | Mon Oct 31 1988 18:00 | 3 |
| What happens when an irresistable force meets an immovable object?
[ No fair to answer if you have already read Asimov's explanation. ]
|
571.73 | Thermodynamics 101 | TLE::SAVAGE | Neil, @Spit Brook | Mon Oct 31 1988 20:28 | 3 |
| Re: Note .69:
To contain universal solvent, lower temperature to its freezing point.
|
571.74 | I know who's number 2 | CAM::MAZUR | | Tue Nov 01 1988 15:14 | 7 |
| re: .71
Who's number 2 ??
The Browns, of course. ( Sorry for the bathroom humor )
|
571.75 | | EAGLE1::EGGERS | Tom,293-5358,VAX&MIPS Architecture | Tue Nov 01 1988 16:17 | 1 |
| YOU are number 6.
|
571.76 | | KAOFS::S_BROOK | Here today and here again tomorrow | Wed Nov 02 1988 18:40 | 5 |
| re .-1
I am NOT a man, I am a FREE number
|
571.77 | Are We Not Men? | SKIVT::ROGERS | But Otto, what about our relationship? | Wed Nov 02 1988 22:06 | 1 |
| We are Devo.
|
571.78 | Here's another one... | HSSWS1::DUANE | Send lawyers, guns, & money | Thu Nov 03 1988 21:29 | 12 |
| My own personal favorite stumper:
Did Adam and Eve have navels?
------------------------------------------------------------------
On the subject of the sealed container with the ice cube that
turns into steam, if the box were weighed in a fluid ( as is air )
the _weight_ would be different if the system as a whole had
increased in volume, making it less dense, but its _mass_ would
still be the same. If the box were weighed _in a vacuum_ before
and after, both the _mass_ and the _weight_ would be the same.
|
571.79 | Something to talk about over the fruit! | LAMHRA::WHORLOW | Prussiking up the rope of life! | Thu Nov 03 1988 23:39 | 9 |
| G,day,
No... but Adam must have had a scar from the op!
:-)
djw
|
571.80 | lojiggle innit | UNTADI::ODIJP | Elefanten springen nie | Fri Nov 04 1988 11:14 | 15 |
| Re .78
> Did Adam and Eve have navels?
Given that God was supposed to have made Man in his own image ,
this would rather depend on whether God had a navel .
Which , of course , depends on whether God had a mother .
Which he obviously did , or he wouldn't have known what a woman
should look like .
Ergo , therefore and thus , the answer must be "yes" .
John J
|
571.81 | Big Bangs and wiggy astro stuff | TSG::KELLEHER | Not me, but an incredible simulation | Mon Nov 14 1988 23:16 | 30 |
| RE: .22
> Here's one...
> If scientists can see from the earth an equal distance in all
> directions, then for all practical purposes, are we not the center
> of our universe?
> Bill
Actually, yes. But it's messier than that.
The mathematics turns up the same result for every location
in the universe. That is, no matter where you are in the
universe, it seems you're in the center. Thus -- given
our current understanding of things -- there IS no center,
yet everyplace is the center.
Nastier still: There was this Big Bang Thing, right? About
15 billion years ago. Doosh!, everything comes rushing out
of a single point. Implies a center, doesn't it? Same thing.
Though I wish I could explain this one better, it comes to the
same thing. The Big Bang WAS from a single point, but that
single point was everywhere. Yeeks.
And now...
What is the sound of Helen Keller clapping with one hand
in a forest when she falls over?
|
571.82 | | MICLUS::PITARD | Back in exile..Now at TAY2-1 | Tue Nov 15 1988 01:18 | 8 |
| >And now...
>What is the sound of Helen Keller clapping with one hand
>in a forest when she falls over?
I thought we determined that there is no sound unless someone
else was there??? ;^)
|
571.83 | What makes teflon stick to the pan?? | OASS::B_RAMSEY | My hovercraft is filled with eels. | Thu Mar 09 1989 02:48 | 0 |
571.84 | "We're number 7!" | ERICG::ERICG | Eric Goldstein | Thu Jun 08 1989 17:27 | 8 |
| .71> Why are *all* football teams #1? After all, their fans say so...
I attended Cornell University, one of eight schools in the Ivy League.
I vividly remember the final football game of my senior year, against Columbia.
Cornell had a perfect record -- all losses -- going into that game, but
defeated Columbia 21-7. (This gives you an idea of how bad Columbia was.)
The title of this note is what the Cornell fans chanted during the game.
|
571.85 | animal, mineral or American Express card? | COOKIE::DEVINE | Bob Devine, CXN | Thu Jun 08 1989 19:19 | 11 |
| After seeing an ad for a "Psychic Fair" recently I wondered
if that is not rather solid proof against.
STUMPER: Why must psychics advertise? If they really did have
true psychic power wouldn't they either (i) no about the person
seeking them without having to wait for a telephone call?; or
(ii) be able to subliminally advertise by sending out a sort
of mental ad?
[ by the way, I mentally made your NEXT UNSEEN command bring you
to this note ;-) ]
|
571.86 | eeenie, meenie, chili-beanie.... | LESCOM::KALLIS | Anger's no replacement for reason. | Thu Jun 08 1989 23:13 | 19 |
| Re .85 (Bob):
>STUMPER: Why must psychics advertise? If they really did have
>true psychic power wouldn't they either (i) no about the person
>seeking them without having to wait for a telephone call?; or
>(ii) be able to subliminally advertise by sending out a sort
>of mental ad?
(i) because the empty barrel makes the loudest noise.
(i[a]) because they also know the other person has to know
about _them_.
(ii) [and forgiving, though noting, the split infinitive]
a receiver need not also be a transmitter.
A true psychic needing money wouldn't have to advertise, though.
He or she could seek fortunes easier ways, like dowsing for treasure
or winning at gambling.
Steve Kallis, Jr.
|
571.87 | Cynicism rules.... | CURRNT::PREECE | Whose garden was this ? | Fri Jun 09 1989 11:44 | 6 |
| re .-1
How many psychics pay fire or accident insurance every year?
Surely they should just take out the insurance on the day before
the fire ?
:-))
|
571.88 | ... lightning | LESCOM::KALLIS | Anger's no replacement for reason. | Fri Jun 09 1989 16:06 | 16 |
| Re .87:
>How many psychics pay fire or accident insurance every year?
>Surely they should just take out the insurance on the day before
>the fire ?
>:-))
Reminds me of a story.
A man was considering taking out fire insurance. He asked the agent,
"Suppose I took out a policy today, and tomorrow my warehouse burned
down. What would I get?"
The agent replied, "Probably ten to fifteen years."
Sterve Kallis, Jr.
|