Recent content by pseudovector

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    Magnetic field of a moving charge

    A moving charge is a non stationary current distribution, so the last two formulae are no longer valid to describe its magnetic field.
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    Why does everything goes to equilibrium?

    You got it the other way around; it's not that thing tend to go to places we declare to be equilibria, but instead, we observed where things like to go to and according to that declared them to be equilibria. Moreover, equilibria are states where the total force is zero. Hence, when something is...
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    How Do You Calculate the Lifting Capacity of a Helium Balloon?

    use archimedes's equation: g * V * dp where g - gravitational acceleration, V - volume, and dp the difference between the densities of the matter inside and outside the volume V.
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    Phase Velocity of Plasma Wave > c

    There are a lot of such paradoxes, where something goes faster than light. The solution is that you can never use them to send information or energy faster than the speed of light.
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    Find Answer: How Does a Fan Work?

    Normal forces are perpendicular to the surface, so whenever a fan wing hits a molecule, it accelerates it in the direction perpendicular to the plane of the wing.
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    Blackett effect and Earth's magnetic field

    Whether this phenomenon really exist is of little importance to me. What I'm interested in is how he got to that formula. Btw, neutral rotating masses do produce minute magnetic field due to small effects like thermal current fluctuations, centrifugal forces, gravity etc.
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    Blackett effect and Earth's magnetic field

    I'm looking for information on Blackett's effect in general and the derivation of his fomula in particular. [PLAIN]www.stardrive.org/Jack/blackett1.pdf[/URL]
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    Gauss' Law and a uniform surface charge

    You got the right results.
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    Electric Heating Coil: Potential Difference in 3.5 mins

    The solution for this problem should not involve capacitanc, charges etc. It's much simpler. First you calculate the amount of heat the water absorbed. Heat=specific heat * mass * temperature difference The heat is the energy that the resistor transferred to the water, in a certain amount of...
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    Increasing the amount of volts would have an effect

    I think there's a limit to the amount of magnetization you can induce in a ferromagnet. If you get all the spins to point in the same direction you get maximum magnetization. In general, ferromagnets behave in a very complicated way. Moreover, I don't even think there's a rigorous physical...
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    Diff eq of mechanical system w/ friction with zero input

    Claude meant you should use phasors to describe the oscillation. The phasor for a frictionless spring would be x=A*exp(i*w*t) (A- amplitude, w - angular frequency, t- time, i- sqrt(-1)). Notice that when you take the real part of a phasor, you get back the more familiar form of the displacement...
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    Does magnetic field do any work

    First, although static magnetic fields can't do work, time varying magnetic fields can. Second, whenever work is done under the influence of a static magnetic field, some external source will have to supply the energy require (as opposed to an electric field that can do work on its own). Let's...
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    Preference for lower energy states?

    Potential energy emenates from force, so where there is an energy difference, there will be a force that drives the system towards the lower energy state.
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    Integrating EM Energy Density: Is E=hf?

    The behaviour of the classic electric field in the vicinity of a point charge reveals that the classical theory has an inherent error, and therefore cannot fully describe reality. Very close to charged particles, this theory breaks down and aught to be replaced with a more precise theory, like qed.
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