# Search results

1. ### I Can windows frost over in space?

I thought about this pretty hard, can windows frost over in space? I'm pretty sure they don't or can't after giving it a bit of thought. This is just a curiosity of mine. So first I believe the correct question that we're trying to answer is: Can a window get colder than interior air faster...
2. ### A 3-star triangular orbit possible?

Apparently 3-star systems aren't really 'doable' as in two stars, with one in-between- but nested binaries are possible. So is it 'possible' for 3 stars to maintain at least a somewhat stable triangular configuration?
3. ### I What's an eigenstate

What is an eigenstate in relation to the Schodinger equation? We've been working with this stuff but I don't exactly understand what that is. I know of linear algebra eigenstates or eigenfunctions but I don't know if they are directly related.
4. ### I Classical uncertainty

In Quantum Mech. we learned about classical uncertainty, and then Heisenberg's uncertainty principle which comes from it. The way it is in the book is, the preceding chapter talks about how the superposition of lots of waves ∑ gives you these groups, and things like group velocity comes from...
5. ### RC circuit black box circuit modeling

Homework Statement I have a red mystery box which contains a 20, 50, 100, and 200,000 ohm resistor (one of each and ONLY one.) There are three terminals on the box you can plug a voltmeter into... testing A-B I got 60k, testing A-C I got 140k, and testing B-C I get 120k ohms. So this is a bit...
6. ### B Uncertainty calculations?

I know the rules to experimental uncertainties with addition and subtraction, but what about division? For instance here The light bulb was measured to have 1.27 ±.05V by the DMM in parallel. Using the DMM in series, its current drawn was .202 ±1A. As a result its resistance was approximately...
7. ### Evo-devo questions

I would appreciate some help explaining some things about evo-devo. The way it's presented in class makes no sense at all. I have desperately tried wikipedia but it just did NOT help in explaining anything. Would appreciate some elucidation on my questions from the great physics forums... So...
8. ### Linear algebra, can A be one-to-one given a case

Homework Statement Given an nxn matrix, if a b exists so Ax=b has no solutions, can A be one-to-one? Homework Equations I understand that as a linear transformation, you need things such as (to be one-to-one as a linear trans) 1. n pivots 2. Only the trivial solution exists to Ax=0 Ax=b...
9. ### Multivar; Path length, and average y-value over it

Homework Statement Letting c(t) =(t2,t,3) for 0<t<1 (Really it's a smaller than or equal to sign) 1. Find the length of the path 2. Find the average y coordinate along the path Homework Equations What we're given in the book: (These equations are not necessarily relevant) (formula 1) l(c)...
10. ### Finding x of a mapping in R4

Homework Statement Linear algebra:[/B] Find all x in R4 space that are mapped into the zero vector for the given matrix A A= | 1 -4 7 -5 | | 0 1 -4 3| | 2 -6 6 -4| Homework Equations None.... it's linear algebra. Don't ban me. The Attempt at a Solution I tried RREF on this after...
11. ### Is a subset of linearly independent vectors indep?

Homework Statement True or false. If v1.... v4 are linearly independent vectors in 4D space, then {v1,v2,v3} is also linearly independent. There's a hint: Think about (c for different constant) cv1+cv2+cv3+0*v4=0 I know that linear independence means there's only the trivial solution... which...
12. ### Can you rearrange vectors in a set? And another misc questn.

Suppose you have a set of vectors v1 v2 v3, etc. However large they are, suppose they span some area, which I think is typically represented by Span {v1, v2, v3} But I mean, if you're given these vectors, is there anything wrong with rearranging them? Because there's a theorem- that "an...
13. ### Multivar calculus final (1)

Homework Statement I had a rather tough multivariable calculus final, and the class was creamed by it. Apparently the professor thinks a 40% average is okay. But here is a portion of the problems. Please help me solve 'em. I'm not exactly sure if I'm taking the right path in these, but I did...
14. ### Lightbulb burnout

So I purchsaed this 6300 lumen light bulb, clear white glass, with a tugsten fillament. I have this small desk lamp that used to have some 30 or 60 watt light bulb installed. I replaced that with the more powerful one, but.... why did the more powerful one burn out? One day, it just burned out...
15. ### Effect of noise cancelling audio equipment

Noise cancelling earbuds/headphones differ from noise isolating earbuds/headphones. Noise isolation just keeps the sound out, whereas noise cancellation actively produces sound in order to "cancel" noise. I understand how this works technologically, however do these sound waves cancel out so...
16. ### How to estimate the power of a laser pointer

Not sure if this is the right place, but I'm hoping to ask two questions: 1. I shine a laser pointer at a mirror at night, and the reflecting beam glaces off of my eye. Obviously it's quite bright, and I want to know if this has caused any serious damage. Of course I shut my eye, but apparently...
17. ### LHC vs SSC

The SSC that was planned to be built in Texas was cancelled, and was supposed to produce protons of about 20 TeV? Can anyone tell me exactly why it would have been much better? For instance, discovering the higgs-englert would have been easier, and sooner, had we used the SSC- but what other...
18. ### Kitchen condensation

So I'm having an argument.. and I just can't explain this in a way that manages to be convincing. So there are two pots in question: One is a special pot made out of a supposedly special material, and has a very tight lid. Once the lid is on, I observe that if you simply poured water on the top...
19. ### Logistic equations?

Would really appreciate some help on this. Homework is due really early in the morning tomorrow, and I've been trying at this for a few hours to no avail. I have a logistic equation, (sorry, I just cannot use latex) dP/dT = (.00777777)P(9-P) (For P positive) Assume P(0)=2 I must find P(65) or...
20. ### Proof of convergence and divergence

Homework Statement Does \frac{2^{n}}{n!} converge or diverge? The Attempt at a Solution Is there more than one way to prove this? I would appreciate a few directions. I've been trying the Squeeze theorem for a long time. I said 1/n! was smaller, but I have no damn idea how to say what's...
21. ### Why is this integral not convergent? Could be a technicality

Homework Statement Wolfram alpha and integral calculator say zero, but my school's HW on webworks does say it's divergent. I don't suppose it's wrong either, since the issue is probably a technicality Arguably, on desmos.com the graph is pretty damn near odd. Homework Equations Int(-inf)(inf)...
22. ### Integration by tables, totally confused

I would really appreciate it if people could help with these integrals. We are supposed to be doing integrals with this table here: http://math.boisestate.edu/~wright/courses/m333/IntegralTablesStewart.pdf Here are the two integrals. Technically, I only need one of them completed...
23. ### Superconductor science fair project?

I'm thinking of doing a science fair project having to do with a superconductor. However, the problem is that I have two things I don't understand, exactly what the science fair is asking for, but that's okay, I can always ask my teacher- And also, how I should start with this superconductor...
24. ### Science fair project with a superconductor?

I would like to do a science fair project having to do with a superconductor... Of course there will be difficulties... But well, basically, can I ask for help here? I'm just making sure that people aren't already saying "No...." and shaking their headsd.
25. ### Very brief summnation question

If there is a sum: i=1, and ends at N Why, if there is an N, is it considered as a constant. As opposed to an i inside of a summnation. I would understand that if for example, there were a Z, Q,E, or W, it's a non-variable. But N, that's ON top of the sum! Wouldn't it.. like turn into...
26. ### Approximating this integral with midpoints

I have an integral from 0 to 1, of sin(x2). I need to, with n=5 rectangles midpoint approximate it. I've figured that I need something like i=1 and ending at 5 (right?), and the equation is just sin(x2) Δx Delta x is 1/5. Are those the correct steps? I think that all I need to do.... is...
27. ### Can someone explain this summation definition to me?

A=limn→∞Rn=limn→∞[f(x1)Δx+f(x2)Δx+...+f(xn)Δx] Consider the function f(x)=4√x, 1≤x≤16. Using the above definition, determine which of the following expressions represents the area under the graph of f as a limit. I knew the correct answer was \sum \frac{15}{n} (4√x+\frac{15i}{n}) I figured...
28. ### Very very short question on second derivative

What does it mean when I have to find the second derivative of a circle at a given point? (Implicit diffing) In specifics, the equation is 9x2 +y2 =9 At the point (0,3) You don't really need the rest at all, but it was just my process. This seems to make no sense. first D'v 18x+2yy'=0 Second...
29. ### Beta decay and inverse beta decay is different?

So in beta decay I know a neutron can decay into, proton, electron and antineutrino (Or, neutrino, since they're both the same?) But anyhow, regardless of the neutrino, in neutron stars electron degeneracy doesn't hold and electrons combine with photons to form neutrons. But isn't that...
30. ### Really fundamental cross/dot product questions

So I've been working on physics homework and we have some vector/dot product questions. This is really long, but the questions I have really are rudimentary at best. I have seven total questions. You're given two vectors that only have an x and y component, A, and B, and the positive Z axis...