## Search found 110 matches

Mon Jul 24, 2017 8:18 am UTC
Topic: 1867: "Physics Confession"
Replies: 182
Views: 26517

### Re: 1867: "Physics Confession"

We do have a good answer for the hair/balloon/lightning thing ... it's called the tribolectric effect. What's wrong with that? Too empirical? Beware ontic dumping; If you answer "Why does static charge build up when rubbing a ballon on hair?" with "because of the tribolectric effect&...
Tue Oct 25, 2016 2:45 pm UTC
Forum: What If?
Topic: What-If 0152: "Flood Death Valley"
Replies: 43
Views: 32251

### Re: What-If 0152: "Flood Death Valley"

keithl wrote:No, a hole must be straight down,

Why?
Mon Oct 10, 2016 8:26 am UTC
Forum: Logic Puzzles
Topic: Pirate's Dilemna
Replies: 9
Views: 6928

### Re: Pirate's Dilemna

Soupspoon wrote:AIUI, no.

Not sure how I missed that the senior has deciding vote in the two pirate case.

measure wrote:
Spoiler:
This changes the 5-pirate solution as well.

Spoiler:
Not a lot though, it's still the case that the two pirates that get 0 in the 4-pirate case now gets 1.
Tue Oct 04, 2016 12:49 pm UTC
Forum: Logic Puzzles
Topic: Pirate's Dilemna
Replies: 9
Views: 6928

### Re: Pirate's Dilemna

Question leaves open the assumption of how a pirate would compare some reward in the current scheme with the potential, but not certainty, for a higher reward by a later pirate. If there is only one pirate he gets 100 gold. If there are two pirates one pirate will be thrown overboard, and the other ...
Tue Aug 23, 2016 8:48 am UTC
Topic: 1723: "Meteorite Identification"
Replies: 30
Views: 9881

### Re: 1723: "Meteorite Identification"

Thu Nov 12, 2015 9:15 am UTC
Forum: Logic Puzzles
Topic: Kings on a Chessboard
Replies: 6
Views: 3517

### Re: Kings on a Chessboard

Is an exhaustive search of the game tree possible? Max number of moves is 62 and the will only be a few times where you have 7 spaces to go to, most times quite a few less. Perhaps an intelligent exhaustive search where you start with landgrabbing and play "intelligently" Exhaustive searc...
Tue Nov 10, 2015 1:34 pm UTC
Forum: Logic Puzzles
Topic: Escape the Frictionless Circle
Replies: 156
Views: 69236

### Re: Escape the Frictionless Circle

Actually! : Any movement of your limbs will shift your COM, thus it will shift the COM of the gold + you system as well. The system will get a net acceleration and then you just wait... No. Any movement of your limbs will also shift the rest of your body so that the COM remains constant. If you mov...
Tue Oct 27, 2015 8:59 am UTC
Forum: Logic Puzzles
Topic: "Shoot for the moon. If you miss, you may hit a star."
Replies: 8
Views: 4849

### Re: "Shoot for the moon. If you miss, you may hit a star."

Sandor wrote:Once you've escaped Earth, you'll be orbiting the Sun with a similar orbit to Earth's, so with an orbital velocity of around 30 km/s. It only takes another 12 km/s (in the right direction) to escape the Sun.

'True. Still outside Apollos delta-v budged though.
Mon Oct 26, 2015 8:15 am UTC
Forum: Logic Puzzles
Topic: "Shoot for the moon. If you miss, you may hit a star."
Replies: 8
Views: 4849

### Re: "Shoot for the moon. If you miss, you may hit a star."

The case of the apollo mission is zero. Apollo did not have enough velocity to escape earth. In order to hit a star other than the sun you would need enough velocity to escape the solar system. That is you would need to escape earth with an extra 42.12km/s. In order to hit the sun you would need to ...
Fri Oct 16, 2015 7:51 am UTC
Forum: Logic Puzzles
Topic: Five Birds, Five Doors
Replies: 1
Views: 2055

### Re: Five Birds, Five Doors

I can do it in 7. And all guess will be "The hawk is behind door number X", I never ask about any other bird. [*]Locate the Hawk in at most 4. (The hawk can be moved when I guess hawk, but only if I select the door of the raven. If I do and this moves the hawk, it moves to hawk to the ...
Thu Oct 15, 2015 9:40 am UTC
Forum: Logic Puzzles
Topic: Simplified
Replies: 5
Views: 2483

### Re: Simplified

rhino721 wrote:yeah solotion is unique, u have to use special principle to solve it

Presumably the modulus -1 answer was not the answer you where looking for, so the solution is not unique.
Thu Sep 10, 2015 8:37 am UTC
Forum: Logic Puzzles
Topic: Anti-Gambler's Fallacy
Replies: 162
Views: 27980

### Re: Anti-Gambler's Fallacy

So you're asked to teleport yourself to the hypothetical scenario where you are already certain that the coin is biased 70-30 to give wins (choose any method that you want that would have given you that certainty) and make a decision. If 8000 loses in a row are enough to shake your beliefs, then yo...
Wed Sep 09, 2015 9:09 am UTC
Forum: Logic Puzzles
Topic: Anti-Gambler's Fallacy
Replies: 162
Views: 27980

### Re: Anti-Gambler's Fallacy

(the point has always been, that if after enough tries you get some very unlikely outcome, then there's nothing stopping it from happening the very first try. Happening on the very first try doesn't mean there's "predesign" at work. Your own existence* was probably less likely than the pr...
Tue Sep 08, 2015 9:36 am UTC
Forum: Logic Puzzles
Topic: Anti-Gambler's Fallacy
Replies: 162
Views: 27980

### Re: Anti-Gambler's Fallacy

You, and other 10^10^10^10^10^10^1.1 people are put on a chamber, and all of you play the game 8000 times. You get 8000 failures in a row. What now? Are you as surprised? From the 10^10^10^10^10^10^1.1, how many did you expect to get your result? I am still just as surprised. I expect a huge number...
Tue Aug 25, 2015 1:45 pm UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

there are too many replies from everyone for me to keep up with!! I know, it's actually a bit annoying, I feel that we are stepping on each others toes. Still I feel I need to reiterate my last question to you; If you see two blue-eyed persons, and no one have left on day 1 or day 2, do you leave o...
Tue Aug 25, 2015 12:19 pm UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

As a counter example to your "The rules is all you need" lets look at a 2 person scenario. stekp has already stated that the 2 person scenario doesn't fit his prerequestites. Q2: I see one other blue eyed person, called A. But if I put myself in A's shoes, I know A must be able to see eit...
Tue Aug 25, 2015 11:22 am UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

All that is required is that all models to have at least one blue-eyed person in order to make the Guru redundant. I believe I am still waiting for you to tell me on which day I can say something about my eyes in the case that I can see two blue eyes. In my interpretation, the situation is this: As...
Tue Aug 25, 2015 11:04 am UTC
Forum: Logic Puzzles
Topic: July 3rd, 2015 New York Times Puzzle
Replies: 14
Views: 6062

### Re: July 3rd, 2015 New York Times Puzzle

No, I tried both negative and fractional numbers. Despite what it said, I got quite a few "no" answers as it seemed too simple It's because most people keep trying ascending numbers and getting yes'. It's when you insert something like 0 0 0 that you're doing it right, and...
Tue Aug 25, 2015 9:03 am UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

stekp wrote:All that is required is that all models to have at least one blue-eyed person in order to make the Guru redundant.

I believe I am still waiting for you to tell me on which day I can say something about my eyes in the case that I can see two blue eyes.
Mon Aug 24, 2015 12:35 pm UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

Q1: I see no other blue eyed people, my own eye colour is unknowable, therefore I never leave the Island. Obviously in that case the Guru's statement would be required to provide new information. Q2: I see one other blue eyed person, called A. But if I put myself in A's shoes, I know A must be able...
Thu Aug 20, 2015 12:07 pm UTC
Forum: Logic Puzzles
Topic: Rethinking Blue Eyes - A Logic Puzzle
Replies: 97
Views: 15668

### Re: Rethinking Blue Eyes - A Logic Puzzle

... Despite what others say in this thread, I strongly argue that this provides *no new information* to the islanders. Everyone already knows that there are at least 99-blue eyed people on the island, and therefore already knows the Guru can see someone with blue eyes. ... I say that the count begi...
Fri Jun 05, 2015 8:29 am UTC
Topic: 1516: "Win by Induction"
Replies: 103
Views: 29959

### Re: 1516: "Win by Induction"

Reasoning with infinity is tricky. If you double the number of pixels on your screen an infinite number of times (by halving each pixel an infinite number of times), do you wind up with a countably or uncountably infinite number of pixels? ... I can't post links, but searching for any of these will...
Wed Nov 12, 2014 12:38 pm UTC
Topic: 1446: "Landing"
Replies: 1143
Views: 224921

### Re: 1446: "Landing"

BlitzGirl wrote:I probably should have asked this before, but why is Philae headed straight for that sarlaac pit?

EDIT: It's not a sarlaac pit of course, it's a giant blowhole. Because cometwhale.

Actually I think it's a target reticle.
Wed Oct 22, 2014 11:27 am UTC
Forum: What If?
Topic: What-If 0116: "No-Rules NASCAR"
Replies: 60
Views: 21351

### Re: What-If 0116: "No-Rules NASCAR"

ilduri wrote:ligature = using a single glyph to represent two letters (eg., the æ in encyclopædia)

æ is a single letter. It comes after z and before ø in the alphabet.
Mon Sep 01, 2014 10:30 am UTC
Forum: News & Articles
Topic: 12-yo girls stab friend 19X to impress Slenderman (meme)
Replies: 44
Views: 17223

### Re: 12-yo girls stab friend 19X to impress Slenderman (meme)

Yeah, it's going to be lovely sticking two 12 year olds in prison with probably paroling out in 25-30+ years time. What wonderful people we'll release into society when all they've grown up in is criminal element and no appreciable tradeskills to sustain a life at 40. It just makes me scratch my he...
Wed Aug 27, 2014 8:00 am UTC
Topic: 1403: "Thesis Defense"
Replies: 52
Views: 20460

### Re: 1403: "Thesis Defense"

mekily wrote:I see "The (Effects/Evolution) of Thesis Displays on Moods". "Effects" makes more sense with the sentence, but the word looks more like "Evolution". Something's still not quite right, but that's what I see.

The Evolution of Thesis Defence in Mordor
Mon Aug 18, 2014 10:42 am UTC
Topic: 1409: "Query"
Replies: 66
Views: 21566

### Re: 1409: "Query"

Meh. Who designed that schema? The age and hours_since_watching_porn fields, I guess, represent events in time but instead of being actual timestamps, they're intervals counting backward from NOW()? And, from context, it seems they use two different units, neither of them seconds. They could be cus...
Mon Aug 11, 2014 11:00 am UTC
Topic: 1406: "Universal Converter Box"
Replies: 162
Views: 42350

### Re: 1406: "Universal Converter Box"

Fobs wrote:Gotta say. Macro USB made me laugh.

Yes, we are all familiar with Micro USB. But Macro USB is impossible and has never been observed.
Wed Jul 30, 2014 11:37 am UTC
Forum: Logic Puzzles
Topic: Grid 4 by 4 with numbers and letters
Replies: 5
Views: 3509

### Re: Grid 4 by 4 with numbers and letters

thefargo wrote:So the blank spot is a decimal point.

Well spotted.

Considering that OP asked for a single upper or lower case letter I would say 'c' is the letter we are after.
Mon Jul 07, 2014 11:04 am UTC
Topic: 1391: "Darkness"
Replies: 81
Views: 16580

### Re: 1391: "Darkness"

How long would it take for you to accidentally wish for something you regret, seconds too late? As long as I can regret it, it should not be that much of a problem. I am more worried about the wishes that, seconds to late, I am unable to regret. Also what constitutes a wish in this context. While n...
Thu Feb 06, 2014 3:36 pm UTC
Forum: What If?
Topic: What-if 0082: "Hitting a Comet"
Replies: 59
Views: 16080

### Re: What-if 0082: "Hitting a Comet"

you know now that a supersonic baseball will only get 130 feet. Well no because the approximation doesn't hold for subsonic speeds. So what you know is that a supersonic baseball will be subsonic after 130 feet. - Giving an upper bound for the length of a throw as 130 feet + how ever far a baseball...
Thu Feb 06, 2014 3:33 pm UTC
Forum: What If?
Topic: What-if 0082: "Hitting a Comet"
Replies: 59
Views: 16080

### Re: What-if 0082: "Hitting a Comet"

The gist of it is; for an object traveling faster than the speed of sound in a medium, in order to penetrate into the medium it will have to push the particles of the medium forward. This transfers momentum from the object into the medium. And, when the object have travelled a distance equal to it'...
Thu Feb 06, 2014 4:44 am UTC
Forum: What If?
Topic: What-if 0082: "Hitting a Comet"
Replies: 59
Views: 16080

### Re: What-if 0082: "Hitting a Comet"

OK. I'll bite. Why is it impossible to throw (launch) a baseball from NYC to San Fran? Is it because it will burn up from reentry? Curious, Randy Randal has described a method of estimating how far an object can potentially travel trough any given medium, originally given by Newton iirc. Unfortunat...
Tue Oct 22, 2013 2:45 pm UTC
Forum: What If?
Topic: What-If 0068: "Little Planet"
Replies: 70
Views: 19511

### Re: What-If 0068: "Little Planet"

Overall I feel that Randall fails to answer the question in this case.

OTOH the answer might be simple.

The moon doesn't have an atmosphere. Because it lacks the mass to retain one. The escape velocity of the little planet is significantly lower.
Thu Sep 19, 2013 7:57 am UTC
Topic: 1266: "Halting Problem"
Replies: 83
Views: 21399

### Re: 1266: "Halting Problem"

This is possibly the most arbitrary problem I've ever come across, and one of the most pointless. At least "Who put the bop in she-bop-she-bop-she-bop?" has some flow to it. Can anyone explain why the "halting problem" matters or is any different to something like "Given a ...
Thu Sep 19, 2013 7:44 am UTC
Topic: 1266: "Halting Problem"
Replies: 83
Views: 21399

### Re: 1266: "Halting Problem"

How does the Halting Problem entail the Principle of Explosion? Not the Halting Problem, but its "solution" by Randall. See below. ... Now, Randall's "solution" basically tells us that any proposition can be proven true by such an algorithm. Of course, it's not what Randall mean...
Tue Sep 10, 2013 4:32 pm UTC
Forum: What If?
Topic: What-If 0062: "Falling With Helium"
Replies: 68
Views: 18729

### Re: What-If 0062: "Falling With Helium"

The to note in this installment is that xkcd is apparently incorporated.
Tue Aug 13, 2013 2:13 pm UTC
Forum: What If?
Topic: What-If 0058: "Orbital Speed"
Replies: 106
Views: 70942

### Re: What-If 0058: "Orbital Speed"

However, we see that the astronauts feel weightless. Is this due to their sideways movement? And, if so, why don't they keep accelerating until they start really falling into the Earth? Are they "losing" speed due to the curving around the Earth? Or, are they just feeling mostly weightles...
Tue Jul 09, 2013 12:50 pm UTC
Topic: 1190: "Time"
Replies: 107493
Views: 53493217

### Re: 1190: "Time"

I wonder how many of us have had birthdays during Time. I know I have. Count me in. I completed n revolutions around the Sun on June 30th. n-1 is a square number; n+1, a number divisible only by two primes, one of which is 3; n+3 is a prime. Happy belated 50 th ! Or 122.- Although that is a bit unl...
Tue Jul 09, 2013 10:39 am UTC