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1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 2:04 pm UTC
by HES
Image
1670

Title: The laws of physics are fun to try to understand, but as an organism with incredibly delicate eyes who evolved in a world full of sharp objects, I have an awful lot of trust in biology's calibration of my flinch reflex.

If he really believes in the laws of physics, he'll just step back into the third dimension and be fine.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 2:44 pm UTC
by Echo244
I like this. The gap between the belief and the understanding is neatly understated.

I am, however, disappointed by Black Hat Guy. Just a big heavy object. No spikes?

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 2:54 pm UTC
by Sjö
Echo244 wrote:I am, however, disappointed by Black Hat Guy. Just a big heavy object. No spikes?


He will soon light the fuse.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 3:14 pm UTC
by gewoonm
Isn't he just working on the interdisciplinary project?

http://xkcd.com/755/

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 3:18 pm UTC
by SuicideJunkie
There is an obvious problem with that setup that will cause a collision:
The slack in the rope means the swinging arc is going to have a larger radius than expected.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 3:30 pm UTC
by Keyman
It's Foucault's POW-dulum, right?

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 3:31 pm UTC
by gewoonm
@SuicideJunkie: Don't worry, I measured, the line is 220px long. It'll hit straight in the face when it's at its the lowest point.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 3:39 pm UTC
by Soupspoon
Echo244 wrote:I am, however, disappointed by Black Hat Guy. Just a big heavy object. No spikes?
It obviously wasn't fashioned by a moody dwarf...

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 4:05 pm UTC
by cellocgw
I always wanted to hide at the far side of the stage when some prof. ran this demo on himself - ideally he'd stand facing away from the pendulum, secure in the knowledge that it won't touch him. Then I give it a little push ...

For additional credit:
I recall a carny game where you let a weight go and only win if it hits the bowling pin on the backswing. Since the oscillation period is the same in the x- and y- directions, you have to start with a different velocity in the two axes (I think... :oops: ). Or initiate chaotic behavior and hope for the best.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 4:34 pm UTC
by Coyne
If I were him, I wouldn't worry about the laws of physics. I would worry about the laws of black hat guy.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 4:42 pm UTC
by Scheod
cellocgw wrote:For additional credit:
I recall a carny game where you let a weight go and only win if it hits the bowling pin on the backswing. Since the oscillation period is the same in the x- and y- directions, you have to start with a different velocity in the two axes (I think... :oops: ). Or initiate chaotic behavior and hope for the best.


Is this the game you're talking about?
https://www.youtube.com/watch?v=8lkft0YpeiA

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 5:02 pm UTC
by cellocgw
Scheod wrote:
cellocgw wrote:For additional credit:
I recall a carny game where you let a weight go and only win if it hits the bowling pin on the backswing. Since the oscillation period is the same in the x- and y- directions, you have to start with a different velocity in the two axes (I think... :oops: ). Or initiate chaotic behavior and hope for the best.


Is this the game you're talking about?
https://www.youtube.com/watch?v=8lkft0YpeiA


Yep, that's the one

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 5:09 pm UTC
by Flumble
Coyne wrote:If I were him, I wouldn't worry about the laws of physics. I would worry about the laws of black hat guy.

There's a physicial law that states the distance to BH guy is inversely proportional to the likelihood of death (per time of course).
Now to find the exact constant*...

*which, incidentally, is in m/s, so it's likely the velocity of that weight at its lowest point. Or there's a BH relativity law and that 'constant' is the velocity at which BH is coming towards you.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 7:49 pm UTC
by Soteria
gewoonm wrote:@SuicideJunkie: Don't worry, I measured, the line is 220px long. It'll hit straight in the face when it's at its the lowest point.


Yeah. I *do* believe in the laws of physics, and that ball is definitely going to hit him. Though I would argue his eyes aren't the things that are in most danger of being damaged, so maybe black hat is right and he shouldn't be flinching, per se.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 11:04 pm UTC
by Heimhenge
cellocgw wrote:I always wanted to hide at the far side of the stage when some prof. ran this demo on himself - ideally he'd stand facing away from the pendulum, secure in the knowledge that it won't touch him. Then I give it a little push ...

For additional credit:
I recall a carny game where you let a weight go and only win if it hits the bowling pin on the backswing. Since the oscillation period is the same in the x- and y- directions, you have to start with a different velocity in the two axes (I think... :oops: ). Or initiate chaotic behavior and hope for the best.


If by "initiate chaotic behavior" you mean "put some spin on the swinging weight" or "leave some slack in the tether before letting go so it jerks around" ... yeah, that could do it. If you're lucky. Nobody can really "control" chaotic motion, since it's all about sensitivity to initial conditions. Well, maybe BH guy can control chaos. Otherwise, the laws of dynamics are against you.

I actually beat this game. Once. Won a cute stuffed panda for my wife. You have to JUST miss the pin on the way in, and let air drag work its magic.

Re: 1670: "Laws of Physics"

Posted: Wed Apr 20, 2016 11:09 pm UTC
by OP Tipping
If he really believes in the laws of physics, he won't flinch.
. He'll leap.

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 1:06 am UTC
by Soupspoon
Heimhenge wrote:Well, maybe BH guy can control chaos.

At the physical level, that's more Beret Guy's field of expertise. BHG's expertise is perhaps more the Aggressive Social Engineering subset (and, arguably, this is what he's been aiming at... as well as Cueball).

Strange that nobody (that I've seen, apols if I've missed it) has referenced the Neil deGrasse Tyson scene. Either the original or the humorously remixed version.

The 'vanilla' version, here, surprisingly. (There's also apparently YouTube versions, perhaps of both types, if you search - but YouTube works too badly on my system to use.)

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 1:54 am UTC
by Bomb Bloke
gewoonm wrote:@SuicideJunkie: Don't worry, I measured, the line is 220px long. It'll hit straight in the face when it's at its the lowest point.


This is accounting for the fact that pixels aren't round, right...?

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 3:12 am UTC
by Gingercat
SuicideJunkie wrote:There is an obvious problem with that setup that will cause a collision:
The slack in the rope means the swinging arc is going to have a larger radius than expected.


BHG would be fully aware of this, and isn't letting on.

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 5:34 am UTC
by JimsMaher
One of the more pervasive lessons of US basic military training aims to get rid of, in part, the flinch mechanism. I've seen officers with graduate degrees laugh loudly from simply making someone flinch. And yet, when all is said and done, they'll say, "sometimes it's good to flinch". They call it conditioning.

Does anyone miss the indoctrination of lunkhead sergeants actually barking, inches from your ear?

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 6:00 am UTC
by Gargravarr
Carl Sagan's Contact reference?

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 12:33 pm UTC
by PM 2Ring
AFAIK, Feynman did it first.
Michael Scott wrote:"There were 183 of us freshmen, and a bowling ball hanging from the three-story ceiling to just above the floor. Feynman walked in and, without a word, grabbed the ball and backed against the wall with the ball touching his nose. He let go, and the ball swung slowly 60 feet across the room and back - stopping naturally just short of crushing his face. Then he took the ball again, stepped forward, and said: "I wanted to show you that I believe in what I'm going to teach you over the next two years."

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 1:03 pm UTC
by StClair
There's a part of me that thinks that if the guy can't figure out what's going to happen when the anchor point is almost directly above him, he deserves what he's about to get.
(That part probably wears a black hat.)

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 1:44 pm UTC
by rmsgrey
What's the initial velocity of the ball?

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 2:16 pm UTC
by orthogon
Gingercat wrote:
SuicideJunkie wrote:There is an obvious problem with that setup that will cause a collision:
The slack in the rope means the swinging arc is going to have a larger radius than expected.


BHG would be fully aware of this, and isn't letting on.

It would be more interesting if BHG's attempted victim were Beret Guy, to whom the laws of Physics don't necessarily always apply...

Re: 1670: "Laws of Physics"

Posted: Thu Apr 21, 2016 4:37 pm UTC
by Mikeski
StClair wrote:There's a part of me that thinks that if the guy can't figure out what's going to happen when the anchor point is almost directly above him, he deserves what he's about to get.

This seems too simple for BHG. Are we sure the other end of the rope isn't rigged to collapse on his target, and the bowling ball is just a distraction?

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 12:42 am UTC
by Heimhenge
Yeah, could be. Or maybe the other end is attached to a helium balloon with enough buoyancy to make the cannonball just skim over Cueball's head? That would be "trusting physics."

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 12:44 am UTC
by Samik
Heimhenge wrote:I actually beat this game. Once. Won a cute stuffed panda for my wife. You have to JUST miss the pin on the way in, and let air drag work its magic.

Or, you were the one guy that weekend the carnie let win, so as to convince everyone else it's not a scam.

JimsMaher wrote:Does anyone miss the indoctrination of lunkhead sergeants actually barking, inches from your ear?

Oh yeah, I've got all kinds of stockholm syndrome. It's much easier from a good temporal distance to see all the humor in / absurdity of the process. Time has worn away everything but nostalgia.

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 1:16 am UTC
by Mikeski
Samik wrote:
JimsMaher wrote:Does anyone miss the indoctrination of lunkhead sergeants actually barking, inches from your ear?

Oh yeah, I've got all kinds of stockholm syndrome. It's much easier from a good temporal distance to see all the humor in / absurdity of the process.

Another immutable law of physics. Comedy = Tragedy + Time.

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 2:59 am UTC
by Gingercat
Mikeski wrote:
Samik wrote:
JimsMaher wrote:Does anyone miss the indoctrination of lunkhead sergeants actually barking, inches from your ear?

Oh yeah, I've got all kinds of stockholm syndrome. It's much easier from a good temporal distance to see all the humor in / absurdity of the process.

Another immutable law of physics. Comedy = Tragedy + Time.


Well, "comedies" were originally tragic in nature instead of what we now consider comedic, so this makes sense ;)

Re: 1670: "Outlaws of Physics"

Posted: Fri Apr 22, 2016 3:06 am UTC
by Eternal Density
gewoonm wrote:Isn't he just working on the interdisciplinary project?

http://xkcd.com/755/
But which one?
Image
(thanks to svenman for making the image, and Sustainabilizer for the event)

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 3:14 am UTC
by addams
Soupspoon wrote:
Strange that nobody (that I've seen, apols if I've missed it) has referenced the Neil deGrasse Tyson scene. Either the original or the humorously remixed version.

The 'vanilla' version, here, surprisingly. (There's also apparently YouTube versions, perhaps of both types, if you search - but YouTube works too badly on my system to use.)

Thank you.
I am glad you posted the link.

That allowed me to find this:
https://www.youtube.com/watch?v=DVSYA1RnSMQ

I flinched and I jumped.
And; I laughed. oops.

Oh! Eternal Density!
Thank you for the image.

I'm so glad for ... (sniff-sniff)

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 3:21 am UTC
by RogueCynic
Physics is based on mass, but mass is not accurately defined or measureable. That implies the term "Laws of Physics" is a misnomer.

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 6:03 am UTC
by MrNumbers
I must admit, I don't understand the joke.

As a physics fan, I know that the velocity of the weight is just going to be its difference in height, which isn't that large.

As a film industrialist, I know that it doesn't take much height for a weight that significant looking to result in a seriously hefty dentist bill. A light that big swinging off a rigging was still enough to crack through two of a mate's front teeth.

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 7:29 am UTC
by Copper Bezel
Did you watch the original version of the Tyson video? It's a classic demonstration that's been common for decades. The strip is playing on it by posing a completely different demonstration apparatus and design in which the poor victim knows how the original demonstration is meant to go, but not why, and is thus going to end up with a hefty dental bill.

Re: the edited video, I have to point out as I did the first time I saw it that it's inaccurate, because vs. Neil Tyson, the weight would flinch.

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 1:04 pm UTC
by Neil_Boekend
MrNumbers wrote:I must admit, I don't understand the joke.

It is a joke version of the pendulum experiment. The normal experiment is safe, because the bowling ball won't go higher than the position it was released at. But it's scary because there is a freaking bowling ball coming at your face.
The position of te right guy (Queball) is not what you'd usually choose. He is directly below the anchoring point so the ball will have maximum speed. He's going to have his face bashed in.
See ExplainXKCD

Re: 1670: "Laws of Physics"

Posted: Fri Apr 22, 2016 1:32 pm UTC
by orthogon
Neil_Boekend wrote:
MrNumbers wrote:I must admit, I don't understand the joke.

It is a joke version of the pendulum experiment. ...

I think what confused me is that the title text relates to the properly conducted experiment, not BHG's version. That's very common, perhaps even the norm, for xkcd - the comic and the title text are often separate responses to the same thing - but if you don't recall the original experiment it can be hard to follow.

Re: 1670: "Laws of Physics"

Posted: Sun Apr 24, 2016 10:05 am UTC
by gcgcgcgc
If you really believe in the laws of physics, you both will and won't flinch, simultaneously.

Re: 1670: "Laws of Physics"

Posted: Mon Apr 25, 2016 2:41 am UTC
by Soupspoon
gcgcgcgc wrote:If you really believe in the laws of physics, you both will and won't flinch, simultaneously.

If I bothered with sigs, that'd be sigworthy. Just saying.

My hat is off to you. (I know it's off, but I don't know how fast it actually came off, when it did....)

Re: 1670: "Laws of Physics"

Posted: Mon Apr 25, 2016 3:36 am UTC
by Mikeski
I'm sure suggesting a quantum superposition at that scale, while being both observed (BHG) and interacted with (bowling ball), merits at least a five-yard penalty.

(Not that the distance matters, but making a physicist measure something in yards is a penalty in itself.)