# Search results

1. ### Looking for a good workbook or website

Hello f(r)iends! I'm a first year undergraduate physics major, in my first electricity and magnetism class, and I feel like I need more practice than what is assigned in the online homework. If you could recommend a good workbook with lots of exercises and if possible solutions (not just...
2. ### Pick my class for me!

While I'm not so indecisive as to completely let others pick my class for me, I would like your 2 cents on the matter of what I should take. So I have to take one lab science outside of my major (physics), and I have narrowed it down to three: programming for scientists/engineers, chemistry (the...
3. ### Electricity and Magnetism Book

I'm a first year undergraduate taking my first electricity and magnetism class, and going through all the classic material: Coulomb's law, electric fields, flux, capacitors, etc. And the book I have explains the material relatively well, but I feel like I'm missing out on so much by just being...
4. ### Integral trouble

Homework Statement \inte^{2x}cos(x)dx Homework Equations The Attempt at a Solution This isn't exactly a homework question, but it's close enough: it's from my old Calculus book (Larson), and I've been stuck on it for awhile. I just need a little hint or something. I've tried a...
5. ### The Limit of Moore's Law

While there are various estimates to the year in which we will not be able to continue adding transistors to a given area on a silicon chip, the typical guess is between 2013 and 2018 [1]. Given that there will eventually be a limit to how small we can make the transistor (due to quantum...
6. ### Spheres on the GRE

"Two small spheres of putty, A and B, of mass M and 3M, respectively, hang from the ceiling on strings of equal length l. Sphere A is drawn aside so that it is raised to a height h0 and then released. Sphere A collides with sphere B; they stick together and swing to a maximum height h equal to "...
7. ### Related rates problem (involving a cone)

Homework Statement Gravel is being dumped from a conveyor belt at a rate of 30 cubic feet per minute. It forms a pile in the shape of a right circular cone whose base diameter and height are always the same. The height of the pile is increasing at a rate of ____ feet per minute when the pile is...
8. ### Why do Jupiter's moons line up?

So I took my telescope out last night and got to actually, really see Jupiter for the first time and it was amazing! While I was looking at it I could see it has 4 moons (though I later found out it has way more than that, but the ones I observed were the big Galilean moons). Another thing I...
9. ### Medical What are the chances I'll inherit schizophrenia from my father?

Given that I'm not a psychologist or therapist, I don't know much about the disease or even his diagnosis, but he is paranoid and talks of his phone being tapped, hidden cameras, has grandiose ideas, claims experiencing things that could only be hallucinations, and makes illogical connections...
10. ### Weighing the languages

So I just graduated from high school and am heading to college with the intention of getting a BS in physics. I took a semester of programming in Pascal my senior year, but had to drop the class the second semester (to get a freakin' art credit to graduate. God**** arts...), so I didn't learn...
11. ### Bobby McFerrin Demonstrates the Power of the Pentatonic Scale

http://www.boingboing.net/2009/08/01/bobby-mcferrin-hacks.html" [Broken] Many of the comments below the video and on other websites point out that it is pretty incredible that the audience knows the pentatonic scale and easily follows what McFerrin wants them to do. McFerrin, at the end of...
12. ### Two cars driving 30 and 40 mi/hr is like hitting a brick wall at 70 mi/hr

I hear this from people sometimes. Upon hearing about a bad head on collision, I will hear a person promptly add the two speeds together and claim the wreck for the drivers is as bad as slamming into a brick wall with that new speed (S = s1+s2). Is this really a good analogy? I'm not so sure it...
13. ### Fresh Drinking Water

http://www.ted.com/talks/michael_pritchard_invents_a_water_filter.html" [Broken] I thought this was a neat little video demonstrating an idea that might save a lot of lives and people from the dread that is diarrhea. I sort of want one! :P
14. ### Suggest items to bring to college!

So I'm trying to figure out all the stuff I'll need to buy for my room/school when I get to university in a couple weeks. I found quite a few items http://www.oldeducator.com/top_100_things_to_bring_to_colle.htm" [Broken]. What would you suggest a new college kid should have? Anything handy...
15. ### Could you be charged for this?

If the police had been called and he stayed, could he have been convicted of anything?
16. ### Find the effective force constant ke

This isn't really a homework problem, but I've been going over these Yale problem sets for physics 200 (http://oyc.yale.edu/physics/fundamentals-of-physics/content/resources/problem_set_3.pdf" [Broken]), and I'm having trouble with one of the questions. Homework Statement Two springs have the...
17. ### Does this website work for you?

"[URL [Broken] Direct [/URL] Click it and see. It isn't working for this computer, which sucks because I just ordered a laptop from there. Thanks.
18. ### News IOUSA: the Movie

http://vimeo.com/2119049" [Broken] Has anyone seen this movie? How did our budget get so out of hand? What can we do to balance it and get out of debt? The film doesn't really give any options to fix the problem.
19. ### Medical How bad are steroids for you?

Awhile back I watched a documentary on the use of steroids in America called Bigger, Stronger, Faster. It seemed to look at steroids not from the angle of a horrid poison no American would touch with a 20 foot pole, but from the angle that it's simply a drug to treat patients with muscle atrophy...
20. ### What can I see?

So I just got my dads old telescope out, cleaned it, and installed new motors and cleaned the primary and secondary mirrors, and it's ready for use! It's a reflector with a 4-3/8" primary mirror, and I wonder: what can I see with this thing (besides the moon, obviously)? I know this is a super...
21. ### String theory is not science!

"String theory is not science!" So there seems to be a lot of people bashing String Theory for not being real science (real science being theories with predictive/explanatory power). For instance: https://www.amazon.com/dp/061891868X/?tag=pfamazon01-20&tag=pfamazon01-20...
22. ### Just look around you

I wonder how well this would go over in a fifth grade science classroom. :biggrin:
23. ### Hailstone Sequence

Suppose you pick a random integer n. If it is even, divide the number by 2, if it is odd, multiply it by three and add 1 and repeat. People think that no matter what integer you pick, it will always end up oscillating between 4, 2, 1, 4, 2, 1, 4, 2, 1...But no one has proved it yet. I looked it...
24. ### Is there gravity on the moon?

http://www.phys.ufl.edu/~det/phy2060/heavyboots.html Do you think this is actually true? If so I'm speechless.
25. ### Software Evolution?

So I was reading http://www.damninteresting.com/?p=870#more-870" and was astounded by the results Dr. Thompson produced. Basically, he used the principles of evolution to get the results he wanted. Is there a name for this type of research? Other examples? I'm very intrigued by it. I wonder how...
26. ### Physics Forums ratings killed every new year!

http://www.alexa.com/siteinfo/physicsforums.com Look at those drops! Apparently everyone is too busy popping champagne bottles open on the new year to help kids figure out projectile motion. I bet the trend will happen again in 2010! :eek: What will we do!? Who will explain to the Calculus I...
27. ### Big Bang and the Stars

So my first question is, how do we know how many stars are in our galaxy? And the second is, how do we know the big bang started with a singularity (as opposed to, say, the universe being a few light years wide and then start expanding 13.7 billion years ago until it reached our present size)...
28. ### Online place to learn proofs?

I really, really suck at proving things. Do you know of any free online resource one could use to master proving things? I know enough math up to about one semester of calculus, a bit about sentential logic and a little bit of set theory, but even still, past finding a trig identity or...
29. ### Studying with music in the background?

So I'm not big on blaring death metal from a \$20 boom box while doing Calculus problems or anything, but I'll often put some light classical music on in the background while studying, or the occasional rock and roll at a fairly low volume. My question is, how does this affect one's ability to...
30. ### Dot Product Issues

Homework Statement Vector A and four other vectors that have the same magnitude but differ in orientation. a) Which of those other four vectors have the same dot product with A? b) Which have a negative dot product with A? http://img195.imageshack.us/img195/7079/40191924.th.jpg [Broken]...