Physics Problem

Kamko · #1 03/16/2005, 08:23 PM

Ok is anyone taking college physics here? I need help with this problem:

There's a cube with length l=2.5cm in xyz space and there is a uniform magnetic field throughout the region with components Bx=+5 T, By=+4 T, and Bz=+3 T. Now how would one procceed to calculate the magnetic flux, phi, through the +z, +x, and +y faces of the cube?!!! Grrr, I'm about to smash my Ti-86 so if anyone wants to save my calculator help!!!

Fishtale7 · #2 03/16/2005, 08:28 PM

Start by drinking alot of beer and then pray very hard that you pass this class.

Sloth · #3 03/16/2005, 08:59 PM

Internet says:
"The contribution to magnetic flux for a given area is equal to the area times the component of magnetic field perpendicular to the area."

So wouldn't you just multiply the area (0.025m * 0.025m) of each face of the cube by its corresponding component of the magnetic flux?

For Bx, its 5 * (0.025 *0.025).

just speculatin

JazzMan · #4 03/16/2005, 09:02 PM

This thread either makes me feel very dumb, or really cool.

luceneck · #5 03/16/2005, 10:01 PM

Jim,

You are a cool idiot

Wish I could be cool.....

SVTour · #6 03/16/2005, 11:05 PM

Wayyyy to many people posting homework problems lately.

Magnetic flux can be easily derived by unsing the second level homogeneous differential equation in its basic form. To start, y"+y'+y=f(x). Substituting the f(x) for the the length, the results of the preceding selection complete the general solution to the homogeneous equation, and can be computed easily. You must assume that Y2 and Y1 are linear...which X Y and Z should all be.

If you don't like that approach, then you need to look at B=phi/A. The unit of magnetic flux density is the weber per square meter (also called the tesla T). Older units still used in calculating this is the gauss (G) where one tesla = 10^4 gauss. In order to run this method, you should have an angle at which the flux passes though the field...and keep in mind, the earth's magnetic flux density is ~ 1/2 G

Choose your poison for solving...

Okay...I need a life now.

VoidRaven · #7 03/16/2005, 11:07 PM

My brain hurts......

masson · #8 03/16/2005, 11:09 PM

WOot I am Excieted for next year ........

surfy · #9 03/16/2005, 11:13 PM

Does this mean you know how to do long division?

Kamko · #10 03/17/2005, 07:11 AM

SVTour thanks for the tip, but although I'm already through with calculus B/C, my physics class does not require [READ: the teacher hates when you use calc] calc, and the problem with phi=BA is that there would be a compoenent theta [the field would not be perpendicular] therefore the equation becomes phi=B*A*cos[theta] and I have no idea how to figure that out in 3dim. space.

SVTour · #11 03/17/2005, 08:33 AM

What was Theta defined by your problem? I have a feeling your instructor is expecting you to know a hidden value here...

der_wille_zur_macht · #12 03/17/2005, 10:03 AM

I have a physics problem. I want to be able to zoom around the universe faster than the speed of light, but physics says it's impossible.

Muttling · #13 03/17/2005, 10:29 AM

Quote:

Originally posted by der_wille_zur_macht
I have a physics problem. I want to be able to zoom around the universe faster than the speed of light, but physics says it's impossible.

Actually Einstein's theory that light speed being the upper limit has been recently been brought into question so there may be hope.

Of course there is also the issue of recent discoveries that the speed of light in a vacuum is not constant as we once thought.

spamin76 · #14 03/17/2005, 10:36 AM

You know - I've always had a problem with physics...

zenguitar · #15 03/17/2005, 01:10 PM

"Let's get physical!"

I know, I'm not helping...

Einstein was totally wrong, the upper limit is warp 10, duh!!

Crusty Old Shellback · #16 03/17/2005, 01:20 PM

Quote:

Originally posted by der_wille_zur_macht
I have a physics problem. I want to be able to zoom around the universe faster than the speed of light, but physics says it's impossible.

Borrow the time machine from Zengutair or Fat Man, depending on which time slot your in, that Fat Man got from Ebay. You should have no probelms then getting around.

vermonter310 · #17 03/17/2005, 01:23 PM

It's actually been in question for some time. I also believe it was that information couldn't travel faster than light.

Quote:

Originally posted by Muttling
Actually Einstein's theory that light speed being the upper limit has been recently been brought into question so there may be hope.

Of course there is also the issue of recent discoveries that the speed of light in a vacuum is not constant as we once thought.

BrianD · #18 03/17/2005, 03:33 PM

Quote:

Originally posted by Muttling
Of course there is also the issue of recent discoveries that the speed of light in a vacuum is not constant as we once thought.

Are we talking a Hoover vacuum here? I don't think there is any room for light in my vacuum. It is full of dirt, lint, dog hair, dust bunnies, and the various life forms that live in everyone's carpeting. I do have headlights on it, which I have never quite figured out, because I rarely have the desire to vacuum the floor at 3:00 am. Even if I did, I probably wouldn't rely in my vacuum's headlights. I can't find the high beam, and I the last time I vacuumed in the dark with my headlights off, some moron in an Orrick cruised by and just about blinded me, and I couldn't even flash him. I had to pull of the carpet and crashed into the wall. Luckily, my vacuum was equipped with a dust bag, or I could have been seriously hurt.

beerguy · #19 03/17/2005, 03:37 PM

That sucks.

BrianD · #20 03/17/2005, 03:39 PM

Not as well as it used to, it is full of gunk as I mentioned. I will have to throw it out soon and buy a new one.

Maybe this one will have high beams where I can find them.

der_wille_zur_macht · #21 03/17/2005, 03:40 PM

My vacuum has only one headlight. But it's an upright, so I think that's legal.

BrianD · #22 03/17/2005, 03:40 PM

Quote:

Originally posted by BrianD
I couldn't even flash him.

With my headlights, I mean.

der_wille_zur_macht · #23 03/17/2005, 03:41 PM

Quote:

Originally posted by BrianD
Not as well as it used to, it is full of gunk as I mentioned. I will have to throw it out soon and buy a new one.

Maybe this one will have high beams where I can find them.

Just put it in reverse and blow the dirt back out. Then you'll have something to vacuum with all the new suckage.

BrianD · #24 03/17/2005, 03:41 PM

Quote:

Originally posted by der_wille_zur_macht
My vacuum has only one headlight. But it's an uptight, so I think that's legal.

Why is your vacuum so uptight? I would think it would be laid back with all the drug residue it sucks up at your place.

Kamko · #25 03/17/2005, 03:41 PM

Quote:

Originally posted by SVTour
What was Theta defined by your problem? I have a feeling your instructor is expecting you to know a hidden value here...

I believe you could find the 2-d components of theta by using pythagorean theorem since the components of the field are given but i'm not sure how to proceed from there once you have the angles in zy zx and xy.

Ps. Oh yeah, from the Einstein's famous E=mc2, the speed of light can be viewed as an upper or a lower bound. For those particles that theoretically could travel faster than light, the lowest possible speed would be that of +c but not lower or at c. These particles are called tachyons although a lot of scientists doubt their existence.