Recent content by lampshade

  1. L

    Why do LED throwies last longer than expected with a small 3V watch battery?

    Hello, You've probably already seen sites about "LED throwies" which are little circuits made of An LED A small 3V watch battery A Magnet Some Tape The idea is that you make these and then stick them to different things and the glow and are pretty. Anyway, with that background...
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    Solve for x(t), I just keep seeing 0

    At the time I felt that it was more of a physics problem.
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    Solve for x(t), I just keep seeing 0

    Just find x(t) I left off a 2 in my work that I just noticed and that seems to have changed things a bit. I have to rework some stuff and maybe see where that ends up. As for what E is, I don't know. Nor do I technically know that m is mass, but it seems awfully like they are. They weren't...
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    Solve for x(t), I just keep seeing 0

    Homework Statement \frac{dx}{dt} = \sqrt{2(\frac{E}{m}) -\omega^2 x^2} Homework Equations \frac{dx}{dt} = v The Attempt at a Solution I keep ending up with the statement x=0. \frac{dx}{dt}=\sqrt{2\frac{E}{m} -\omega^2 x^2} Then (dx/dt)^2 =2\frac{E}{m} -\omega^2 x^2...
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    Monopole Moment of a sphere of charge

    Ok, thanks! I think I see what I did wrong!
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    Monopole Moment of a sphere of charge

    The obvious problem that then comes up is that then appears is that I get a 0 term from the second integral that makes my whole monopole moment zero. Is this correct?
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    Monopole Moment of a sphere of charge

    Homework Statement I'm really bad at these type of problems. I'm supposed to find the monopole moment of this continuous charge distribution. its charge is \sigma = const*cos(\theta) Homework Equations p = \int r'\rho(r')d\tau which then since we are doing a surface charge should be p =...
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    De Broglie wavelength of electron

    Homework Statement Show that the de Broglie wavelength of an electron of kinetic energy E (eV) is \lambda = \frac{12.3*10^{-8}}{E^{1/2}} Homework Equations \lambda = \frac{h}{p} E = \frac{p^2}{2m} The Attempt at a Solution I've played around with substituting and things like that, but I...
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    So the question would be:What is the difference between absolute value and norm?

    After studying it some more, I think they do actually mean the absolute value and nothing else. I'm still a bit shaky though so respond with insights if you have any, please.
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    So the question would be:What is the difference between absolute value and norm?

    Hello, I don't know if this is general math or not, but I know it is a simple question that I just don't get so I put it in this forum. I'm kinda rusty at this, but I came across an equation in a book on wavelets that uses the notation | f(t) | inside an integral and I"m not sure...
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    Not an actual hw problem, but it might as well be

    Homework Statement Basically I bought a new 7200 rpm hard drive and I was curious about it since it is a 2.5 inch notebook hard drive. What I was wondering was how many g's were pulled at the edge of the disk while it spun at 7200 rpm Homework Equations \frac{v^{2}}{r} I'm just going...
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    Simple NAND flip flop question

    Thanks a ton for the clarification. I had actually already read the wiki page in the process but I was still a little confused. Thanks again!
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    Simple NAND flip flop question

    something has always bothered me about nand flip flops and their use in memory so I thought I would ask this here and get it cleared up. In a basic nand flip flop like the one found here: http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/nandlatch.html#c1" I understand that there is a...
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    Random MOND theory / dark matter question(possibly really easy to answer)

    I'm also having a hard time calculating the theoretical value of the MOND acceleration. I tried using universal gravitation, the veloctiy of the Earth as it orbits the sun, and the mass of the earth, but I got a value nowhere close in magnitude to what all these websites are saying the value...
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    Random MOND theory / dark matter question(possibly really easy to answer)

    Thanks It took me a while to figure out that OOM meant Order of Magnitude, but I got it. THANKS!
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