Recent content by Earthland

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    How Is Scattered Flux Density Measured from a Ruby Laser in the Atmosphere?

    Homework Statement [/B] An unpolarized ruby laser operated at 0.7 μm is projected vertically into a clear sky to investigate the density of the atmosphere. A detector located 10 km from the base of the laser is used to receive the flux density scattered from the laser beam by air molecules...
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    How to make this circuit easier?

    You understand me correctly. Anyway, it seems I got right answers, only the order of the variables was messed up. The correct values are U_56 = 123.07692307692308 U_25 = 46.15384615384616 U_12 = 30.76923076923077 I2 = 1.5384615384615385 I1 = 4.615384615384616 I = 6.153846153846154 Thank you...
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    How to make this circuit easier?

    I think I reasoned as follows: First, that current trough resistors 12 and 56 is the same (current "I"), thus equations for corresponding voltages U_12/5 = U_56/20 Second, that voltage in the parallel part is equal, thus currents I1 over 25 and I2 over 2-3-4-5 satisfy the eauation...
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    How to make this circuit easier?

    Homework Statement I need to find voltages and currents in the following circuit, using Kirchoff laws. The purpose is not to gain knowledge in electricity, but to write a program that solves a system of equations using Gauss elimination method. I think I wrote correct program, but I also need...
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    Help to form questions regarding wind flow/convection

    Well I'll have to advance my simulations probably, once I'll figure out what could be my problem, yes :D
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    Help to form questions regarding wind flow/convection

    Hello! I'm not sure if this is the right forum for this topic, but my question is very general, not a textbook problem or something like that :) . I work in Comsol where I have imported the topography of mount St Helens and I simulate wind flow around the mountain (as laminar flow) and also...
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    What probability density is used in Brownian motion?

    Homework Statement I have a free Brownian particle and its coordinate is given as a function of time: And its first moment, or mean, is given as But what kind of probability density was used to calculate this first moment? Homework Equations I know that the first moment is calculated...
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    Can someone help me to find some data?

    Thank you very much!
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    Can someone help me to find some data?

    I didn't know where exactly should I post this kind of question :) I need to find experimental values of linear thermal expansion coefficients of copper at various temperatures (ranging 100-1500K); however, as much as I google it I only get coefficients at 20 degrees of celsius, or else there...
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    Vector differential identity proof (using triple product)

    Both v-s produce a scalar field and thus ∇ acting on it produces a vector field, which it must be because another vector is added to it. ∇ acting on only one v means acting on vector field which would produce a tensor field. So there is some kind of relation I should use?
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    Vector differential identity proof (using triple product)

    That's what I thought also, but I blindly followed the triple product structure provided by wikipedia. So should I just change it to ∇(v⋅v) But still, 1/2 is missing
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    Vector differential identity proof (using triple product)

    I can't quite understand what you mean. I kept track of the order according to triple product definition, but what does it even mean to keep track on the v that ∇ is acting on? I can't just make it act on v where it isn't acting on v.
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    Vector differential identity proof (using triple product)

    Homework Statement Need to prove that: (v⋅∇)v=(1/2)∇(v⋅v)+(∇×v)×v Homework Equations Vector triple product (a×b)×c=-(c⋅b)a+(c⋅a)b The Attempt at a Solution I know I could prove that simply by applying definitions directly to both sides. I haven't done that because that is tedious, and I...
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    Kronecker sum of more than two matrices?

    Are you sure? Thank you!
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