What is the correct way to calculate streamlines of a vector field
Hello there, What is wrong with my way of finding stream lines of a vector field? Say I have this vector field: [itex]\vec{v} = x\,y\,\vec{i} + y\,\vec{j}[/itex] You can see a plot here:...
View ArticlePower transferred from the sources to the electromagnetic field
Hello!! In an electro-magnetic context, the power that an electric source of field delivers to the field itself may be written as [itex]p_S = - \mathbf{E} \cdot \mathbf{J}[/itex] where...
View ArticleFaraday cage (hollow conductors)
Hi! I have a question regarding the Faraday cage. I know how a Faraday cage works and understand the principles that make it work and why (potential difference, flux, gauss' theorem...) but I have a...
View Articleabout spring constant and Hooke's law
Hi all, I am reading an online material on elastic force and Hooke's law on spring. The definition of the Hooke's law reads that the restoring force is linear proportional to the displacement of the...
View ArticleYoung's double slit experiment
Why did Young specifically perform a double-slit experiment to demonstrate the wave nature of light, since light will diffract and interfere even through a single slit? Is there something special...
View ArticleFriction for different contacts
Hi all, I know this is a very basic question and has been discussed in various threads.Anyway i would i like to ask this. If the value of friction only depends on coefficient of friction and normal...
View ArticleWhy supercapacitor energy density is so high?
In battery we have (in ideal) case one electron per atom or three elecrons (in case of aluminum) which flow from anode to cathode.In activaded carbon there should be immensely smaller amount of free...
View ArticleConceptual Circuits
I'm just trying to get a conceptual grounding for the circuit problems in our book. So I understand that a circuit maintains a potential difference via redox reactions. The electrons have a desire to...
View ArticleRadius of a curvature for specific force on a seat in a jet
The question is: What is the minimum radius of curvature of a jet, pulling out of a vertical dive at a speed of v, if the force on the pilot's seat is 7 times his weight? The way I thought to answer...
View ArticleElectricity generation - gear mechanics and speed
I watched a documentary recently about electricity generation, and I've been trying to figure out whether an example they provided is actually possible or not in theory. If a big wheel, much like a...
View ArticleMotion of a Spinning Coin
I have several questions about the motion of spinning coins. I won't get to them all in this post, but hopefully some of you can help get me started. (Note: I am a mathematician, not a physicist - that...
View ArticleCurrent in superconductors when a voltage is applied.
Suppose you a have superconducting loop connected to a 9V battery. What is the current through it? With a resistance of 0Ω, [itex]V = IR[/itex] gives ∞. I don't think that can be right... If it were,...
View ArticleCalculate the circulation of vector field
Hello there, I've got a vector field which you can see here: Sketch of the vector field . It is: [itex]\vec{v} = \cos(x)\,\sin(y)\vec{i}-\sin(x)\,\cos(y)\vec{j}[/itex] Say I want to find the...
View ArticleCurious question:Electron/plasma emitter
Would it be possible to harness a microwave's magnetron's tungsten filament portion, along with a other components, to create a electron/plasma emitter?
View ArticleRadial vs Axial Turbine, diff in mechanical stress
I am a hobbyist and I have designed a radial turbine device for use in a tidal stream. I have conducted a couple of experiments to demonstrate that there is less mechanical stress in the radial...
View ArticleVirtual differentials approach to Euler-Lagrange eqn - necessary?
I'm currently teaching myself intermediate mechanics & am really struggling with the d'Alembert-based virtual differentials derivation for E-L. The whole notion of, and justification for, using...
View Articleaccelerated reference frames equation derivation question
my question comes from the portion of the derivation regarding evaluating the rate of change of the principle axis vectors. this begins by supposing a vector, Q, is rotating about axis n by δθ....
View Articlecalculating the magnetic field in solenoid
Just need a question cleared up. If I had a coil wrapped around a core, and I was calculating the magnetic field of the solenoid using B = μnI where n = N/L, I is current and μ is the permeability of...
View ArticleDialectric inserted into capacitor => creation of a double-capacitor
A dialectic of width d is inserted into a capacitor made up of two plates, with the plates being a distance D apart. D>d. Afterwards, the capacitor acts like it is two capacitor connected in series....
View ArticleLinear force acting on axis of rotation
An uniform rod of known mass and length (m and l if you like) is rotating relative to an axis of rotation located at one of its ends. The rotation is frictionless and the angular momentum at a...
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