Recent content by LaissezDairy

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    Schools Give me a reality check on grad school admissions?

    Small update: As well as likely being able to get glowing letters of rec from this current job (at a gov't lab), I'm also going to be having my name on quite a few peer reviewed publications coming from my lab - is this going to be as big a boost as I hope it'll be? Several of the "how to get...
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    Where Did I Go Wrong in Determining the Normalization Constant?

    do you know what a gaussian integral is?
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    Electric field inside a cavity within a sphere

    If the cavity is concentric with the larger sphere, it is uniform - zero. If the cavity is not concentric, then the thing about the gaussian surface is the fact that you have no enclosed charge means that the NET flux is zero on the surface - not that the flux is zero everywhere. It is not...
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    Where Did I Go Wrong in Determining the Normalization Constant?

    You can't break up an integral like that. Think about it. \int x^2 dx = \int x * x dx = \int x dx \int x dx = x^4/4 ?? Also this identity might make it less painful for you: cos(kx) = \frac{e^{ikx} + e^{-ikx}}{2} (Euler's formula)
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    Flow Network - Linear Optimization

    Yes. Those are your six inequalities. Hint: for the next part, it will be helpful to solve each equality for one variable (because usually the easiest way to do an optimization problem with two variables is by graphing the inequalities)
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    Flow Network - Linear Optimization

    Oh, I think you may be overthinking it (and so was I) - you know each inequality, right? (each variable is greater than zero). You know how to express x1 through x4 in terms of x5 and x6, right? If x1 is greater than zero, and x1 equals -20 + x5 + x6, what does it mean about the quantity -20 +...
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    Flow Network - Linear Optimization

    That constraint typically isn't entered into the matrix for LP, the typical LP Min problem goes: Minimize \overline{c}^T \overline{x} Subject to \overline{A} \overline{x} \geq \overline{b} x _1 ... x_n \geq 0 Have you tried constructing the Dual of the problem? Also which two nodes are...
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    Do Bullets Fired Upwards Pose a Risk When They Return to Earth?

    They'd be going at terminal velocity before they hit someone - of course, bullets are specifically designed to have low air resistance and so would have a very high terminal velocity.
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    Schools Give me a reality check on grad school admissions?

    Thanks G01, that's exactly the sort of advice I was after - number one is a particularly useful reality check to hear. I suppose a big question for me is how much does work experience figure into admissions decisions? Because I think that's an edge I have compared to other candidates coming...
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    Programs Should a physics major learn optics?

    I did both an optics course using Hecht and an EM course using Griffiths - I found the EM course significantly more difficult, but that may be partially because of all the new applications/methods of calculus you learn, and having the EM background helps significantly with optics.
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    Pursuing a Career as a Physicist: Tips for 14 Year Olds

    Maths maths maths. There is no point in learning any physics at all unless you are extremely comfortable with maths.
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    Programs Should a physics major learn optics?

    It's definitely useful. I learned some valuable applications of Fourier analysis (applicable to data analysis obviously) and you get to learn and apply lots of maths (because you're starting from the wave equation). It's definitely one of the more useful classes I took in undergrad. It's also...
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    Schools Give me a reality check on grad school admissions?

    Hello, I'm a physics BS and I'm considering pursuing a graduate degree. Ideally I'd like to pursue a PhD in physics, and I'd like a reality check on my chances of admission. What's really putting a damper on things is my mediocre GPA - 2.81 . I'm well aware that this hurts me lots on graduate...
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