UTMC

Fuck my life, WHAT? Quiz on it tomorrow... Better figure it out.

42.

That's all you, bro...

Mole. That's more of a chemistry answer, though.

X+Y over the square of the hypotenuse = a banana.

Seriously though...
http://www.physicsforums.com/

Fucking ______, how do they work?

change majors.

Groove wrote:

X=1




I worked this out in my head over an hour ago and since tried to resist the urge to post it...god, I'm just sad, aren't I?

guitargeek wrote:That's all you, bro...

WORD!!!

Do you know the Greek alphabet? Just write them a pretty little sentence in Greek characters and no one will be the wiser.

blackjoe wrote:English majors never have to deal with shit like this.

Yup....

It's O.K. DG. I immediately had to do it in my head as well. X also = -6 though.

To start off with, I'm sure most of you are familiar with F=ma... Force is equal to the amount of mass you've got, multiplied by the amount you need that mass to accelerate.

Ok, now, each one of those variables is a vector in space (a set of three numbers that tells you the position, velocity, force, or acceleration you are dealing with relative to whatever point of reference; like drawing an arrow from whatever your origin is, say 0,0,0 to whatever your vector value is, x,y,z). Vectors represent both the size and direction of... whatever.

Sigma F on the far left means the summation of forces acting ON an object. In this case, we'll use a bucket of gasoline.

Now say you throw that bucket of gas up in the air with that force F, and you want to figure out what that's going to look like mathematically. The ground, where you are standing, becomes the inertial (non-moving, observer's) reference frame. That frame has its own XYZ coordinate axes. The bucket itself also gets *its* own set of coordinate axes (the relative frame of reference).

The Arel term is the various accelerations going on inside the bucket axes...

d2R/dt2 is the acceleration of the bucket's axes away from the observer's reference frame (like if your bucket had rockets, or was subject to that pesky gravity thing).

The cross product... http://en.wikipedia.org/wiki/Cross_product (which is what each of the X symbols represent) of d.omega/dt and r is the effect of any angular acceleration going on (say, if the rockets are making the bucket spin faster and faster).

The cross product of 2.omega and r is the forces of acceleration the bucket would feel from the gasoline sloshing around. (Coriolis acceleration).

Omega x (omega x r) is the centripetal acceleration, the vector for which is directed from the bit of gas you are concerned with, straight to the axis that the rockets are making the bucket spin on.

Now you take that whole Arel term and stick it up in the integral, and do the integral times the change in mass of the bucket for F=ma (in case your bucket is leaking, or it's raining outside, and you need a really precise equation for the forces effecting your bucket toss, it's really important to do an integral and not just multiply by an average amount of mass, or you might light the wrong neighbor's house on fire).

The total force acting on your rocket bucket full of gas is the summation of the forces of your toss, minus the integral of all that other crap that may be adding or subtracting to the overall forces acting on your bucket at any given point in time.


Now on the RIGHT side of the equation, things get a little more weird. On the right side, we've got non-Newtonian physics going on. F=ma doesn't exactly apply, and the forces acting on the bucket are called "fictitious forces." I am not well educated enough to be able to explain it at the moment, but in a short enough time I will be. The gist of it is that we are now dealing with momentum exerting a force of a kind, instead of... well... force.
In the meantime, if anybody wants to make their brain hurt, go look it up here: http://en.wikipedia.org/wiki/Fictitious_forces

But discounting that glaring hole in my knowledge, here is what the right side of the equation is telling you:

Working from the inside out of the first term, the V times Ro means the velocity of the gas (relative to the observer) that's flowing out of the bucket times the density of that gas, integrated over the change in volume of your bucket itself (so let's say that this is a floppy bucket, and it's not really up to the effort of being tossed; it deforms and the volume gets smaller, and some gas sloshes out because of that).
The d/dt part around that is the rate of change of the deformation of your bucket with respect to time.
Since we've got density times volume times a velocity all going on in that term, that means we are dealing with a momentum. (Density times volume is mass. Mass times velocity is momentum).

Pulling that term all together, you've got the momentum force associated with the change in mass flowing out of your bucket as it changes its volume with respect to time.

Now the last term...

V times Ro again is the velocity of the gas flow out of the bucket, relative to the observer, times the density of your gas.
Multiply that times the dot product of Vr*n
( http://en.wikipedia.org/wiki/Dot_product ) which is the velocity of the gas relative to the *bucket* times the vector arrow that points directly away from the top surface of your bucket (or directly away from the imaginary plane through which the gas flows)
When your bucket deforms, and the gas sloshes out, the deformation also causes a change in the area through which the gas flows. Your nice, perfect, circular bucket is now an ovoid, and that ovoid doesn't have the same area as the circle that it was a minute ago. That's what the dA means at the end of the term.
This is important, because velocity, times density, times area, is the amount of gas you just poured out of your bucket (or amount of anything that just passed through anything, for that matter).

So you take the integral of V*ro(Vr*n)dA and THAT is the momentum force caused by the gas that has flowed out of your bucket.

Add those two terms together, and tickety-boo, they add up to be the sum total of the forces acting on the system.


Still with me?
I know that maybe two of you bothered reading this far.
Congratulations on being a complete and total fucking nerd.
Needless to say, you can take the whole equation apart to figure out whatever position, velocity, acceleration, or force you need to as your soon to be exploding bucket of rocket propelled gasoline sails swiftly and expediently towards your white trash neighbor's meth lab.

The end.
Oh, and for you total fucking nerds that made it this far, you also probably already know about a lot of this shit.
Y'all just go ahead and correct me if you can.
Please.
I've gotta make sure I'm right so I don't frakking fail this class.

I just wrote a 10 page paper on the definitions of americanism in the interwar period and took a 346 level history midterm for which I rote nearly 5 pages in an hour, and I thought, wow noah, you're the coolest smartest little shit ever. then you come along with that fucking bullshit and make me feel like i'm retarded.

WeAintFoundShit wrote:...a bunch of stuff...

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dozer wrote:I just wrote a 10 page paper on the definitions of americanism in the interwar period and took a 346 level history midterm for which I rote nearly 5 pages in an hour, and I thought, wow noah, you're the coolest smartest little shit ever. then you come along with that fucking bullshit and make me feel like i'm retarded.

A coherent, five page paper in an hour is no small feat.
It takes me DAYS to write a five page paper. I've never gotten less than an A paper, and cranking out a five page paper in an hour would almost surely bring me my first F.

Different types of intelligence, my man.

Well you guys are both giving me something to work towards. I get to those crazy maths in a few years and the five page papers work me over, getting there though. Believe it or not though it's the ballet that's the worst. I call my tuesdays and thursdays Days of Humiliation.

You at Cabrillo?

Yeah Cabrillo. You went to Davis right?

I wish you fuckers would get your degrees already. I need someone who can make a good cappuccino.

goose wrote:I wish you fuckers would get your degrees already. I need someone who can make a good cappuccino.

edit: I did read your explanation but I have nothing to offer in the way of help. Made sense to ME once you did explain it, if that helps at all...

I will be making rocket parts.
And trying to design the world's first flying motorcycle.


That's better than a venti, half caff, dry soy latte at 165 degrees, isn't it lawyer boy? BTW, How long were you in school for that law degree?



(Ahhhhh, I'm a douche.)

Anyhoo, I went to Cabrillo for two and a half years. The place is a really good school if you have the right teachers.

Take any bio class you possibly can from Jon Carothers (sp?) Even if you don't need bio. Swear to god. The guy is fucking weird as hell and totally awesome.
Take math from Dave Reynolds, Ed Braunhut, or Dave Viglienzoni.
For the love of god, and all that is holy, do NOT take math classes from Lalu Simsick, and try at all costs to avoid taking math from Eastman. He'll make you cry.

David Lau is one of the best English teachers you'll ever come across.
Christie Vogel is a tough but AMAZING chemistry teacher.
Satoru Suzuki is awesome, clear, and easy as hell (Chemistry)
Josh Blaustein is awesome, and blows shit up whenever he possibly can. (Chem again)

If you need fancy math, do it ALL at Cabrillo. Don't leave any of it hanging if at all possible.

Art History 10 is the best GE on the planet if you take it from Brian Legakis. Easy as hell, and suuuper interesting.

In so many ways, Davis actually pales in comparison to Cabrillo. It's actually kind of disgusting.

Are you going to do the spring dance recital??

Also, there's a few guys at Cabrillo that are great to ride with...

Tristan. He rides an XR650l. He's fucking fast. He's Sebastapol when he signs on here. He briefly had a privateer sponsorship as an Aprilia SuMo rider, but the shop went under. He also downhills like a motherfucker (he's on a Santa Cruz Nomad, I think; you might actually know him from that already.

Matty Nylander. He rides an old, beat up KLR. He's a total surf bro. Good guy.

There's a younger dude named Dave who rides a GSXR600.

There's a flaming red head guy named Ian who rides dirt.

All of them are very, very cool people. Beers, rides, DH runs, surf sessions, whatever.

Tell any one of those guys that you're friends with Kimball, and you're good to go.

Yeah I'm in for fancy math. In fact my academic schedule at Cabrillo runs through 2015, mostly because of all the math. I'm working on the principle that you like what you're good at, and you're good at things you actually do. Therefore if I continue doing all the math I will get good at it, then enjoy it.

This is from the "self-improvement through catharsis_101" course material, yes?

In any case, I can tell you with all sincerity that attaching rockets to a bucket full of gasoline is ill-advised, no matter whose meth-lab you have it aimed at.

I will be making rocket parts.

About 5 years ago or so, I was sitting at the corner of the bar in the local watering hole.
Three guys were having lunch, shirts, ties, pocket protectors. The conversation was about solid state switches, accelerometers, solid boosters, and stuff like that. Eventually I had to stick my nose into their business and ask, "Are you guys talking 'Rocket Science' over there"?
They all looked at each other and said, "Yeah".
Has never happened to me before or since, but working in the construction trades I can;t even count the number of times I've heard, "It aint Rocket Science".
Sometimes it is.

Well, there's little, rocket science going on in the world these days, the principles of physics upon which rocketry are based being well understood by now. "Rocket Scientists" are usually actually Rocket Engineers.

I someday hope to be one of those aerospace engineers, although frankly I think rockets suck. I'd like to be the guy working on whatever the next thing is that'll be cooler than rockets.

SpecialK wrote:I someday hope to be one of those aerospace engineers, although frankly I think rockets suck. I'd like to be the guy working on whatever the next thing is that'll be cooler than rockets.

piccini9 wrote:

I will be making rocket parts.

About 5 years ago or so, I was sitting at the corner of the bar in the local watering hole.
Three guys were having lunch, shirts, ties, pocket protectors. The conversation was about solid state switches, accelerometers, solid boosters, and stuff like that. Eventually I had to stick my nose into their business and ask, "Are you guys talking 'Rocket Science' over there"?
They all looked at each other and said, "Yeah".
Has never happened to me before or since, but working in the construction trades I can;t even count the number of times I've heard, "It aint Rocket Science".
Sometimes it is.

When I lived in Houston I dated a girl who was a rocket scientist working for NASA. And I worked in the construction trades. She wasn't all that smart, she couldn't even roller-blade or change her own oil, she just worked harder than I did in school.
However my degree involed a good deal of physics (and waaay toomuch civil engineering, hated that shit) nd I loved every minute of my physics courses. I failed miserably at calc, which obviously held me back at higher level physics, but I "got it" in a way that I never did with any other subject. I still like to draft out structures and figure out how forces will impact them in different ways. That stupid Android app where you place bombs around a stick frame structure to bring it down below a certain height? I rule at that shit.
Good luck in school, wish I had worked harder...