## Search found 235 matches

- Thu Jun 26, 2014 4:46 pm UTC
- Forum: Science
- Topic: Speed of Propagation of a Magnetic Field.
- Replies:
**116** - Views:
**28929**

### Re: Speed of Propagation of a Magnetic Field.

Sure I could measure distances on the ground instead of rotating the whole apparatus around. But who would come out to my location, measure the distances and check the results. Einstein did just a thought experiment and some calculations (which were done by his wife); there is no proof as far as we...

- Sat Jun 21, 2014 6:16 am UTC
- Forum: Science
- Topic: Speed of Propagation of a Magnetic Field.
- Replies:
**116** - Views:
**28929**

### Re: Speed of Propagation of a Magnetic Field.

P1T1o We used a 50 megahertz dual trace computer interfaced Oscilloscope. The CB transceiver sends out a 27 Megahertz signal. So what is the problem with that. The wave patterns shown were actual printouts, not hand drawings. The control experiment showed that by moving the antenna a distance of 11...

- Fri May 16, 2014 4:58 pm UTC
- Forum: Mathematics
- Topic: Need second opinion. I think I disproved God.
- Replies:
**72** - Views:
**13177**

### Re: Need second opinion. I think I disproved God.

I refuse to believe God uses AOL.

- Fri May 16, 2014 2:47 pm UTC
- Forum: Mathematics
- Topic: Need second opinion. I think I disproved God.
- Replies:
**72** - Views:
**13177**

### Re: Need second opinion. I think I disproved God.

Dr-Evil wrote:Who gets to decide if my hypothetical God counts as a god? I used only the minimum-criteria: extremely powerful and existing.

My Gods are David Dunning and Justin Kruger. Their effect is extremely powerful as evidenced by this thread and they absolutely exist. You can totally just e-mail them.

- Fri Feb 22, 2013 3:49 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Nice! Welcome back. Happy to hear everything is still moving along.

- Sun Sep 02, 2012 2:56 pm UTC
- Forum: Fictional Science
- Topic: Observing the Big Bang
- Replies:
**31** - Views:
**9694**

### Re: Observing the Big Bang

But was there a gravitational event equivalent to the neutrino decoupling of the CNB or the photon release of the CMB? Maybe: if the Theory Of Everything which claims that gravity was once unified with the other 3 forces is correct, then gravity probably decoupled at the end of the Planck era. Well...

- Sun Jul 22, 2012 11:37 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

The concept of a constant is somewhat context dependent. In the example of y = mx + b the slope and y-intercept (m and b) are constants for a given line and the values of x and y are what change as you move along the line.

- Sun Jul 15, 2012 9:30 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Yeah, sign errors are very skilled at sneaking their way into computations. They will subside in time.

Also just to clarify, although im sure you know this. The order doesn't matter but it does have to be consistent. For instance

m = y2-y1 / x1-x2

is incorrect. This would introduce a sign error.

Also just to clarify, although im sure you know this. The order doesn't matter but it does have to be consistent. For instance

m = y2-y1 / x1-x2

is incorrect. This would introduce a sign error.

- Sun Jul 15, 2012 9:15 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

The slope should be the same regardless of the order you put the points into the forumla. Think about it this way: You have two points on a line. They are (x1,y1) , (x2,y2). Now: m = (y2-y1)/(x2-x1) Multiply both sides of the equation by 1. On the left hand side we just write "1" but on th...

- Sat Jul 14, 2012 2:15 pm UTC
- Forum: Science
- Topic: first radiation constant as 3/8th?
- Replies:
**5** - Views:
**2109**

### Re: first radiation constant as 3/8th?

What if thread was lock?

- Thu Jul 12, 2012 11:41 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Sure, computer programming is a good example. Linear Algebra is used all the time in fields like image processing. The application to physics is not that esoteric either. Perhaps there is some confusion about what a vector is? A vector is an object which carries information about both direction and ...

- Thu Jul 12, 2012 11:26 pm UTC
- Forum: Science
- Topic: Extracting energy from a black hole with a laser.
- Replies:
**5** - Views:
**1743**

### Re: Extracting energy from a black hole with a laser.

You might be able to steal some energy from it's spin, by slowing that down. Not sure if you could do much with that energy though. Or if you could do it without using another large mass in the process. There are mechanisms that allow the extraction of spin energy, for instance the Blandford-Znajek...

- Thu Jul 12, 2012 7:32 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Right! So now here's some extra credit: Can you apply this to something physical or practical? Don't over think this. Just try to make a jump from abstraction to application.

- Sun Jul 08, 2012 5:55 pm UTC
- Forum: Science
- Topic: Question about mass and stars
- Replies:
**16** - Views:
**4171**

### Re: Question about mass and stars

Oh sure that's a great clarification. I was just trying to avoid getting into a lot of the details and I ended up with poor wording. Thanks!

- Sun Jul 08, 2012 5:15 pm UTC
- Forum: Science
- Topic: Question about mass and stars
- Replies:
**16** - Views:
**4171**

### Re: Question about mass and stars

Thanks, they do look pricey but an offiial textbook might be worth it, there is only so much you can get from pop science. Pop science books are wonderful for inspiring people to think about these things and thats important! But I think you should start to move on to proper texts if this is what yo...

- Sun Jul 08, 2012 4:17 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

I would actually say you could begin to learn the basics of trig alongside algebra. But really every concept you pick up in basic algebra I would consider key and important. I've seen plenty of kids struggle in Calculus II or III simply because they never developed a strong algebra/trig background.

- Sun Jul 08, 2012 3:46 am UTC
- Forum: Science
- Topic: Question about mass and stars
- Replies:
**16** - Views:
**4171**

### Re: Question about mass and stars

I really wish I knew of a nice 1st year undergrad astronomy text that isn't 100 bucks. I think it would help you a great deal. Usually we assign something like: http://www.amazon.com/Universe-Roger-Freedman/dp/142923153X/ref=sr_1_9?ie=UTF8&qid=1341718944&sr=8-9&keywords=the+universe for ...

- Sun Jul 08, 2012 3:38 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Wait until you start getting into maths that have much more interesting applications in physics like calculus and differential equations. I think that's when things really begin to shine and it only gets better from there.

- Sun Jul 08, 2012 3:05 am UTC
- Forum: Science
- Topic: Question about mass and stars
- Replies:
**16** - Views:
**4171**

### Re: Question about mass and stars

The elements that are the result of fusion are heavier because they have a nucleus with more protons/neutrons. For instance, helium has two protons and two neutrons whereas hydrogen has just 1 proton. Therefore a helium atom is heavier than a hydrogen atom. However, a star like our sun fuses hydroge...

- Sun Jul 08, 2012 2:57 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Yup! There is nothing better than learning things by screwing up. It makes you very aware of that mistake and you always keep an eye out for it until you erase it completely. Working through things yourself with the proper amount of handholding is a great way to reenforce concepts. I'm happy you see...

- Sat Jul 07, 2012 3:39 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Anyway, I was bored at work so I started making up my own formulas, no laughing (unless it's with me :P ). I couldn't remember what the speed of light was, but I knew the average Earth-Sun distance was 93 million miles and it takes sunlight 8 minutes to get here. So if d is the distance and t is th...

- Fri Jul 06, 2012 3:25 am UTC
- Forum: Mathematics
- Topic: Can you have matricies inside of matricies?
- Replies:
**11** - Views:
**4419**

- Thu Jul 05, 2012 9:48 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

BryanRabbit wrote:Or maybe it's because I'm older

As someone who is also a returning astronomy student I can tell you that you should never doubt the power of maturity. Oh, also wanting to escape a job you hate isn't a bad motivator either.

- Wed Jul 04, 2012 7:36 pm UTC
- Forum: Science
- Topic: Higgs and Mass
- Replies:
**20** - Views:
**6442**

### Re: Higgs and Mass

Sorry if you already saw this but is this what you are asking about?

http://en.wikipedia.org/wiki/Higgs_mech ... r_fermions

http://en.wikipedia.org/wiki/Higgs_mech ... r_fermions

- Wed Jul 04, 2012 7:36 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Also if I can offer a word of encouragement: The quantum you are exposed to in popular science and the quantum you deal with in practice are vastly different. In popular books quantum is portrayed as this incredible mystery that no one really understand where everything is dominated by strange pheno...

- Tue Jul 03, 2012 6:27 pm UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

I think we should also mention the importance of quantum and statistical mechanics are essential as they form the basis of radiative transfer which is the study of the absorption, emission, scattering, etc. of light by physical processes. Since you almost always observing light of some form (radio, ...

- Mon Jul 02, 2012 4:19 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

- 58(x^9)(w^7)(x) / 23(x)(w^2)(w^6) = - 58(x^9) / 23w 24(x^4)(w^10)(x^6) / -91(x^7)(w^7)(w^9) = -24(x^3) / 91(w^6) I get what happened to the variables, but how come, in the first example the real numbers (correct my terminology please) stay as they are, but in the second the positives and negative...

- Sat Jun 30, 2012 3:21 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

Ah, great! I'm so glad you started asking questions. :D Best way to learn in my opinion. I would like to add that you should really try and take a lot away from your first question and dopefish's response. The ability to turn a physical scenario into equations (and going the other way of course) is ...

- Tue Jun 26, 2012 3:26 am UTC
- Forum: Mathematics
- Topic: Want to study astronomy... bad at math
- Replies:
**117** - Views:
**31477**

### Re: Want to study astronomy... bad at math

You should use this thread as your tutor. Post problems you're working on, the steps you're taking, and where you're getting confused. I'm sure there's plenty of people (myself included) who would be more than happy to help you through it.

- Mon Jun 04, 2012 1:59 am UTC
- Forum: Science
- Topic: I want to learn (the basics of) quantum! Help?
- Replies:
**6** - Views:
**3336**

### Re: I want to learn (the basics of) quantum! Help?

Unfortunately, those are still fairly expensive books. You might have a hard time finding a good modern book that covers QM at the level you want that isn't almost 100 dollars. Perhaps try Quantum Theory by Bohm. It is part of the Dover series and should be ~10 bucks. It was written in the 50s so it...

- Thu May 24, 2012 12:56 am UTC
- Forum: School
- Topic: Your Schedule
- Replies:
**655** - Views:
**164967**

### Re: Your Schedule

Senior Year Astronomy/Physics Double and Math Minor Galaxies - Dynamics, structure, formation, and all that good stuff. PDEs - Need 3 credits to finish my minor and I wanted one more class with this professor before I left. Senior Thesis Research - Not sure of an exact topic yet. Most likely to do w...

- Thu May 24, 2012 12:44 am UTC
- Forum: Mathematics
- Topic: After calculus
- Replies:
**20** - Views:
**4792**

### Re: After calculus

If you are thinking about going into physics it might not hurt to develop a working knowledge of tensors. Learn what they are, how to do basic calculations with them, how to write familiar computations using tensor notation, etc. etc. It only occurred to me because some people were talking about E&a...

- Sat Sep 10, 2011 7:04 pm UTC
- Forum: Mathematics
- Topic: Vectors and Index/Summation Notation Question.
- Replies:
**0** - Views:
**854**

### Vectors and Index/Summation Notation Question.

Hi, This is homework for a mathematical methods course however I have already worked out a solution and written up my answers so this thread is more an issue of curiosity than anything. The question is: Consider a crystal whose unit cell has basis vectors \vec{e_1},\vec{e_2},\vec{e_3} that are not n...

- Fri Sep 24, 2010 11:10 am UTC
- Forum: Mathematics
- Topic: Symbolic Issues With Matlab
- Replies:
**1** - Views:
**619**

### Symbolic Issues With Matlab

Hi all, I am currently working on a homework question dealing with using Matlab to solve ODEs symbolically. The problem is that the book we have to use was written for Matlab 7 when Maple was still in use. I think that MuPAD in Matlab 2009a is now giving me issues. The original differential equation...

- Tue Jul 20, 2010 8:14 pm UTC
- Forum: Mathematics
- Topic: Homework: Complex Analysis [An Ongoing Adventure]
- Replies:
**9** - Views:
**1799**

### Re: Homework: Complex Analysis [An Ongoing Adventure]

That make any sense? Yeah, for the most part. Given the quicker pace of the class I kinda have to move on for now and I will revisit these problems over the weekend. Thanks for taking the time to type all of that out. Sorry my original sketch was so incoherent I was trying to slip a quick edit into...

- Mon Jul 19, 2010 9:58 pm UTC
- Forum: Mathematics
- Topic: Homework: Complex Analysis [An Ongoing Adventure]
- Replies:
**9** - Views:
**1799**

### Re: Homework: Complex Analysis [An Ongoing Adventure]

Yes, I understand exactly why what I wrote was wrong. I think its because I originally had planned to just type out a rough sentence description or sketch of how I was thinking about things and then it came out as some mangled half-proof. In the future I'll try to be more clear in my intent. We had ...

- Fri Jul 16, 2010 3:28 am UTC
- Forum: Mathematics
- Topic: Homework: Complex Analysis [An Ongoing Adventure]
- Replies:
**9** - Views:
**1799**

### Re: Homework: Complex Analysis [An Ongoing Adventure]

Ah that makes sense. I need to be better about that.

Would that be considered sufficient or is it still merely a sketch of a proof?

Would that be considered sufficient or is it still merely a sketch of a proof?

- Fri Jul 16, 2010 2:07 am UTC
- Forum: Mathematics
- Topic: Homework: Complex Analysis [An Ongoing Adventure]
- Replies:
**9** - Views:
**1799**

### Re: Homework: Very Basic Complex Analysis

I'm sorry to have left this thread hanging. Thanks for the link to the half-angle formulas, they did the trick. One week in and this class has been an interesting crash course in basic proof writing. We are doing planar sets and I understand all of the definitions but sometimes I have trouble puttin...

- Wed Jul 14, 2010 1:00 am UTC
- Forum: Mathematics
- Topic: Homework: Complex Analysis [An Ongoing Adventure]
- Replies:
**9** - Views:
**1799**

### Homework: Complex Analysis [An Ongoing Adventure]

Hey gang, Need a little bump in the right direction with this problem. As stated in the book: Prove that if n is a positive integer, then \left|\frac{sin\left(\frac{n\theta}{2}\right)}{sin\left(\frac{\theta}{2}\right)} \right | \le n , \left \{ \theta \ne 0 \pm 2k\pi \right \} Hint: ...

- Sat Jul 03, 2010 12:35 pm UTC
- Forum: Mathematics
- Topic: Application of differentiation question.
- Replies:
**2** - Views:
**1102**

### Re: Application of differentiation question.

Take the formula for the volume of a cylinder as one equation, then take the given constraint as another equation and then you have all the information you need.

(i) [imath]V=\pi r^2h[/imath]

(ii) [imath]h + 2 \pi r = 120[/imath]

(i) [imath]V=\pi r^2h[/imath]

(ii) [imath]h + 2 \pi r = 120[/imath]