I just registered for the forums, I wanted to say hi. I am really excited to be a barreler, and I can't wait to see everybody again at geddon.

First challenge: teach me something.

Second Challenge: What sort of Cupcake do I like?
Third Challenge: Make that cupcake for me!

Ready
Set
GO!GO!GO!EXPLODE!

Fucking Magnets, how do they work:

To a good approximation:
B = (mu_0 / 4pi) (mu/r^3)

Vak, chocolate cupcakes with strawberry frosting?

And you're first assignment under me, you're sponsor, don't look like a fucking kite the next time I see ya but keep the Russian hat, that shit is ballin.

I'm sold

I'm on board for part of that, but only up to calc 1 & physics 1 (cause I'm a deadbeat scumbag college dropout).

I need a bit more hand-holding (cause fuck you if you think I'm going to wikipedia).

WHAT IS B
WHAT IS MU_SUBWHATEVER
WHY FOURPI
WHAT IS A TESLA
WAS I RIGHT ABOUT MU_SUBWHATERVER? WHAT IS THAT ANYWAYS?

Basically, assume I have nothing except a solid knowledge of SI units, significant figures and a host of physical and chemical laboratory testing apparati.

Bodmin- I'm on it, your right that new garb is definitely in order.

Derian-

B is the magnetic field created by a permanent magnet (for example, a fridge magnet). The unit for magnetic field is the Tesla, and for reference the Earth's magnetic field is about 20 microTesla.

mu_0 is the permeability of free space. Its just a number, although it is important because it turns out to be related to the speed of light.

The four pi comes the field being spread out over the surface of a sphere basically. The surface area of a sphere goes as 4 pi r^2.

The mu (without the _0) is the magnetic moment of the magnet (How "magnetic" it is.) You can either measure it for a specific magnet to find what it is, or try and determine it by looking at the properties of what the magnet is made from.

For a single magnet, everything besides the 1/r^3 is constant. The important thing is that magnets don't interact with each other strongly for very far.

Final question: How do I calculate the magnetic field generated from the winding/rotor interaction in my 1987 Oldsmobile Calais. Furthermore, how would I calculate the cost:energy discrepancy between charging the battery outright via a mechanism with 100% outlet->output efficiency (assuming a sample rate of $0.15/kWh) vs. purchasing a gasoline/ethanol blend of 87 AKI octane rating fuel at $3.40/gallon assuming optimal lubrication, exhaust efficiency and engine RPM:fuel consumption ratio.

Well, you could approximate your alternator as a simple inductor, in which case the formula for the field would be B = mu_0 N I / L. mu_0 is the same as before, N is the number of windings, I is the current that flows through, and L is the length of the alternator. However, it is further complicated by the wires being wrapped around an iron core, which will increase the field.

As for the second question, I you need to find the energy density of 87 octane. Wikipedia gives 9.7 kW·h/L, so using $3.40/gallon, you would get $0.09 KwH. However, that assumes you can get 100% of the energy out of your fuel in your engine, which is physically impossible regardless of the engine design. At the temperatures cars run at, the maximum possible efficiency is about 25%, which means in terms of the energy you can actually use, you would be looking at $0.36 KwH. So, the battery at this point is looking about twice as efficient. There are of course many complications. One thing to consider is that car engines are not designed to get as much energy as possible out of the fuel, but instead designed to get lots of horsepower out of the fuel.

Fuckin nerds

Hahahah, what the fuck. I have no idea what was going on in my head last night.

Well played, W:3D, well played indeed.

I got this: Booze

Well, clearly.

Well well well Wolfenstein. Congrats on being a barreller. Do you have your PhD yet?

Thanks Kazi. I don't have the PhD, but I am doing essentially my master's defense on June 4th. I probably won't get the PhD until spring/summer 2015 at the earliest.

Most awesome thing i've read all week.
I miss you guys.

but as far as your alternator goes you also hafto take into account what is hear by to it wen doing your math to find the output of energy. due to the wiring and other mettle objects and the unshielded nature of an alternator you lose production and or gane it depending on the gage of wire by creating an magnetioce field wen that field passes threw wire it creates electricity and that can interfier with the production of energy.

also i am sad we dident get to hang out and talk at geadon and hope that nose of yours is alright

Yeah, I think its gradually getting better. I can't really feel much with the drugs, they seem to be working. I'll know more when I see the doctor on Wednesday.

Keep us updated man and heal quickly. <3

Went to the doctor today, I have an in place fracture, which apparently just needs time and rest. I'm still incredibly not mobile, but feeling pretty good. I did not have to take the medication today.

Also, he said I should be healed and feeling better (and able to fight!) in a week.

Sorry this is so belated but I'm glad to hear good news. Hope you're still healing up well and feeling better. =)