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Thermodynamic Temperature
Hello, new to these forums I'm trying to complete a basic thermodynamics problem, calculating the thermodynamic temperature of a gas immersed in water at triple point. The problem begins with a table...
View ArticleCell phone works in elevator?!
Very often the principles of faraday cage are extended to non electrostatic situations, i.e. situations involving time varying electric and magnetic fields. This means that the interiors of a metallic...
View ArticleOptics: Concentrating light with a lens
I'm looking at concentrating light (e.g. sunlight) with a lens, and trying to figure out the maximum concentration I can get. If you have a perfectly collimated source, a lens can focus that light down...
View Articlecopper wire and shove it into the positive terminal
If I were to take a copper wire and shove it into the positive terminal of an electrical outlet and then stick the other side of the copper wire into the earth, will current flow??
View ArticleMagnetic field and force
Hello, I was curious conceptually why the B field is perpendicular to the magnetic force. I know its a cross product, but is there some sort of conceptual argument that can convince me, other than...
View ArticleRolling without slipping
I've been having trouble with this topic for a while now. I've re-read the section dozens of times now, but I'm still not exactly clear and I was hoping for clarification on a couple of things. In a...
View ArticleOutgassing of CO2 from a lake after lowering the water level
Hi folks! English is not my native language so please excuse my bad grammar. I am a geology student working on a project about a lake when an interesting puzzle piece - a newspaper article from 1844 -...
View ArticleTemporal and Spatial Coherence
What is the difference between the two in simple terms ?
View ArticleOptical waveguide modes with different speed, what happens?
Hi, I'm new on the forum and I would like to start with a question. I've searched for a reply in old posts with no success. If you can help me to find an answer I'll be very glad. Talking about optical...
View Articleplaying tug of war in space, who wins
what would happen if I played a game of tug in space? I'm considering the gravity to be zero and the mass of the rope is negligible and there is no friction. My mass is larger but the force with which...
View ArticleBesides curl and div how do we know "character" of a vector field
Taking EandM right now and it seems like for a given field A we can tell a lot about it by knowing its curl and divergence.. as one becomes more awesome in physics what other things become important?...
View ArticleThe units for current density don't check out
In my lectures the equation for current density was given as: [itex]J=n*q*vd[/itex] where: n = the number of electrons per unit area q = electron charge vd = drift velocity of electrons If you rewrite...
View ArticleIncreasing flux density increases magnetic force?
Hi! When calculating the attraction/repulsion force generated by a magnetic field should I consider the flux density of both and add them to the calculation? By increasing that vector would it increase...
View ArticleCalculating Helmholtz energy (incl degeneracy)
Hi I'm trying to calculate Helmholtz free energy from definition [itex]\frac{\partial A}{\partial T}=\frac{\partial}{\partial T}(kT\mathrm{ln}\; Z)[/itex]. First [itex]\langle E\rangle=\sum\limits_i...
View Articletorque from inertia
a vehicle is moving at 100 km/hr. the foot is lifted off the accelerator, and the vehicle decelerates, if a mechanism is introduced to absorb the toque from the differential gear(bevel ring gear). and...
View ArticleCalculation of the magnetic field ring current and the magnetic flux t
This work was motivated by the lack of open source analytic formulas for calculating the magnetic field of a current ring at any point in space As the result of the theoretical calculations, which are...
View ArticleResonance in a damped triangular potential well
I have a potential well which is an infinite wall for x<0 and a linear slope for x>0. There is damping proportional to velocity. Basically, it's a ball bouncing elastically off the ground and...
View ArticleSelf consistent maxwells equations
Are there any articles on solutions for simple self consistent systems in EM, as in when the field equations are coupled with the motion of the particles, I would like to explicitly see the energy...
View ArticleAttraction between a charge and a magnet
In physics lab we positively charged a metal sphere then placed a compass near it and both ends of the compass were attracted to the sphere. I know magnetic fields are created by electrons, so I made...
View ArticlePolar Wave Equation
Hi! I've been given the following problem to solve: Consider the azimuthally symmetric wave equation: [itex]\frac{∂2u}{∂t2}[/itex] =...
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