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Physics, etc.
http://www.ferrousmoon.com:80/forums/viewtopic.php?f=55&t=1886		 Page 1 of 1
Author:  FinalWarrior [Sun Aug 16, 2009 8:43 pm ]
Post subject:  Physics, etc.
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"You can't learn shit unless you've got enough sleep, are well fed, and don't feel like barfing in your teacher's face."
Well... that explains why I can't remember a goddamn thing from my physics class. (That's a lie, I can remember a few things - p=f/a, f=ma, q=mcat [or as some say it, "kew equals em cee delta tee"] - but a lot has slipped my mind [e.g., the four basic mechanics equations].)

-- Griffinhart
Author:  IPGhost [Sun Aug 16, 2009 8:48 pm ]
Post subject:  Re: (Need) better news articles
I actually failed science. Or, rather, by my own standard, I did, but for some reason the pass mark for that subject was 30% on the final exam. I got like 30.4%.

Fair, I suppose, given that we did mechanical, chemistry, electrical and nuclear science all in one go, at a higher level, and it was all sort of dumped on us in a very inefficient way. That, and (I swear I'm not kidding) our teacher looked like Michael Jackson.

(When he was still alive).

And no, I can hardly remember anything.
Author:  FinalWarrior [Sun Aug 16, 2009 8:51 pm ]
Post subject:  Re: (Need) better news articles
According to my physics teacher, while he was in college, at one point he took an exam, scored under 50% (IIRC, around 34%) and got something like a B-.

Physics is hard.

(Though fun. Like, ridiculously fun. Or maybe I'm just weird in that I enjoy puzzling out the conundrums of physics at relativistic speeds.)

-- Griffinhart
Author:  IPGhost [Sun Aug 16, 2009 8:56 pm ]
Post subject:  Re: (Need) better news articles
You're just weird.

It might be me, though. For instance, when it came to forces and opposing forces, in the instance of a 1kg ball resting on a table, we were told to think of the resisting force the table provided as "pushing".

Yes, the table was actually pushing against the ball with 1kg of force, which is why the ball remained on the table and didn't go crashing straight through.

I never got over that. I have yet to discover the reality where inanimate objects are capable of exerting force entirely unaided by external factors. I always thought it was just capable of resisting force up until breaking point, but I think I might be wrong.

Nuclear physics were fun, though. Playing with concepts abstracted from (probably incorrect) theories about matter and radiation.
Author:  Soldier of Light [Sun Aug 16, 2009 10:40 pm ]
Post subject:  Re: (Need) better news articles
I love physics. I got an A+ in high school physics and college physics (still just physics I though). My teacher sucked, but it was all really interesting to me.

As for the thing about the normal force: Basically every substance has the ability to generate a normal force (a force equal and opposite to a pressure on the surface of the substance) up to a certain amount. If the pressure on the object exceeds the normal force that can be generated, that results in unbalanced forces and therefore the object is no longer at rest, but begins moving because there is now an external force on it, which is why it breaks.

At least that's how I rationalize it. Sometimes I make things up. But that's pretty much how it works lol.
Author:  IPGhost [Sun Aug 16, 2009 11:07 pm ]
Post subject:  Re: (Need) better news articles
When you hit a wall, you're hitting the cohesive forces between the molecules that make up the wall. The wall isn't hitting back. IT CAN'T.

You shouldn't have to apply this interdimensional logic hack just to explain why your fist didn't go straight through. Really.

Edit: Hold up, how did we get from news articles to molecular forces?
Author:  Soldier of Light [Mon Aug 17, 2009 8:40 am ]
Post subject:  Re: (Need) better news articles
Well if you wanna get that technical... The electrons of the molecules in your hand are repelling the electrons of the molecules in the wall and vice versa. Hence your hand applies a force on the wall and the wall applies the same force on your hand. The wall's molecules are repelling yours.
Author:  FinalWarrior [Mon Aug 17, 2009 8:44 am ]
Post subject:  Re: (Need) better news articles
Quote:
When you hit a wall, you're hitting the cohesive forces between the molecules that make up the wall. The wall isn't hitting back. IT CAN'T.
Only, the wall is hitting back. Those "cohesive forces" you're talking about? That's the wall hitting back. The force doesn't exist if you don't hit the wall, right?

(And then you get into those weird-as-all-hell quantum theories that argue that, if you push against the wall constantly for a long enough time, there is a minute chance that you'll phase through the wall.)
Quote:
Edit: Hold up, how did we get from news articles to molecular forces?
We were talking about how someone can't conceivably, in the year 2020, absolutely lack knowledge in computers. bluechill asked about whether or not he spelled "whether" correctly (he didn't), made a second mistake (spelling "no" as "know"), cpu5594 said he wasn't going to bother correcting again, you quoted your teacher, I extended that quote to apply to my poor physics knowledge, you mentioned not being able to wrap your head around the idea of the normal force, and here we are.

-- Griffinhart
Author:  IPGhost [Mon Aug 17, 2009 12:58 pm ]
Post subject:  Re: (Need) better news articles
Quote:
Only, the wall is hitting back. Those "cohesive forces" you're talking about? That's the wall hitting back. The force doesn't exist if you don't hit the wall, right?

(And then you get into those weird-as-all-hell quantum theories that argue that, if you push against the wall constantly for a long enough time, there is a minute chance that you'll phase through the wall.)
In order to "hit" something you need to apply force to it. Force is a function of mass X velocity. The wall has mass. It has no velocity. The only way it could actively hit back is if it extended in your direction with enough speed to counteract your hit, but from what I can see, walls don't move.

Not in this reality anyway.

As for the phasing-through thing, yes. Theoretically, at some point, the random vibrations in your molecules and the molecules of the wall would allow your hand to slide through. Unfortunately it'll probably go one molecular layer at a time (for the most part), and it'll probably take several million years.
Quote:
We were talking about how someone can't conceivably, in the year 2020, absolutely lack knowledge in computers. bluechill asked about whether or not he spelled "whether" correctly (he didn't), made a second mistake (spelling "no" as "know"), cpu5594 said he wasn't going to bother correcting again, you quoted your teacher, I extended that quote to apply to my poor physics knowledge, you mentioned not being able to wrap your head around the idea of the normal force, and here we are.

-- Griffinhart
Gotta love forums :?
Author:  FinalWarrior [Mon Aug 17, 2009 1:08 pm ]
Post subject:  Re: (Need) better news articles
Quote:
Quote:
Only, the wall is hitting back. Those "cohesive forces" you're talking about? That's the wall hitting back. The force doesn't exist if you don't hit the wall, right?

(And then you get into those weird-as-all-hell quantum theories that argue that, if you push against the wall constantly for a long enough time, there is a minute chance that you'll phase through the wall.)
In order to "hit" something you need to apply force to it. Force is a function of mass X velocity. The wall has mass. It has no velocity. The only way it could actively hit back is if it extended in your direction with enough speed to counteract your hit, but from what I can see, walls don't move.
Oh boy.

You did not just go here with me.

Force does not equal mass * velocity; it's mass * acceleration (see above, in my post: f=ma). That's a huge distinction, by the way - velocity is movement with direction, acceleration is the change in velocity.

The wall does, in fact, have velocity. Movement is relative. Your fist, relative to the wall, is moving. The wall, relative to your fist, is also moving. You're only seeing your fist moving because your perspective relates you to your fist. If we lined a camera up to your fist and had it move at the same velocity, your fist would look immobile while the wall would appear to be slamming into your fist.

Saying that "the wall does not move" is the same as saying "the Sun orbits the Earth" - you're both right and wrong, depending on your perspective.

-- Griffinhart

ETA: I'm splitting these physics posts into their own thread.
Author:  gamers2000 [Mon Aug 17, 2009 2:00 pm ]
Post subject:  Re: Physics, etc.
I think I just died and went to heaven.
Author:  IPGhost [Mon Aug 17, 2009 2:44 pm ]
Post subject:  Re: Physics, etc.
I've noticed that most arguments in the physics community seem to be won whenever the one party is able to magnify the issue to such stupendous proportions that the other side gets lost trying to interpret and respond.

So screw it. I don't have a point to prove.
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