Question about mirrors
Hello, I have a quick question of clarification on convex mirrors. If I have a single convex mirror, is it ever possible that image distance is greater than focal length? Let's assume we are dealing...
View ArticleClik here to view.
On the clockwise rotation of the reflection coefficient with frequency
It is well known that the evolution of the input reflection coefficient, [itex]ρ[/itex], of a LTI causal passive system with frequency, [itex]f[/itex], always presents a local clockwise rotation when...
View Articlemagnetic field due to many wires
Say I have three parallel wires facing north east that run through a square. The first wire goes through the top right edge. The next wire goes through the top left edge and the last wire goes through...
View ArticleFrom Planck's law to derive the stefan Boltzman constant.
The following is the Planck's derivation for black body radiation $${\rho}({\lambda}) d{\lambda}=E({\lambda})*f({E(\lambda}))*D({\lambda})d{\lambda}------equation 1$$...
View Articlehow to find the function for which ∫ √x*√(1+y'^2) dx is...
this is an euler lagrange equation problem from the book- "classical mechanics-John R. Taylor", problem-6.11 find the path function for which ∫ √x*√(1+y'^2) dx is stationary. the answer is- x=...
View ArticleGravitational force from a square plate
I ordinarily would put this up in a homework/ coursework forum, but this isn't either one, its just something I was curious about given that I am in a Mechanics class. So, I have done calculations for...
View Articlefree edition of Purcell, Electricity and Magnetism
Thirty years after learning E&M from the wonderful book by Purcell, I noticed that the copyright page of my dog-eared copy of the 1965 edition includes a notice stating that it is available for use...
View Article[Electromagnetism,optics]How to attack a problem of dielectric tensor?
Hi, I am currently making an effort to solve a boundary value problem of electromagnetic field. The problem is as follows: The region ##y<0## is vacuum. The region ##y \geq 0## is filled with...
View ArticleCenter of gravity of an orbitting body not at center of gravity
It just occurred to me that in the right gravitational field, say, in a low orbit 100 km from the core of a neutron star with a mass equal to that of the sun, an orbiting object's center of gravity is...
View ArticleHow can I determine the maximum load on a surface?
I'm trying to determine what equations I can use in order to calculate the maximum load (in pounds) across a sheet of plexiglass. Could anyone help me look in the right direction? This is just a sheet...
View ArticleWater, Pressure, & Submarines
First of all, I would like to say hello to everyone! I am not sure that this is the right place to post this, or even the right forum. Looks like everyone is very knowledgeable here, and I hope someone...
View ArticleThe thermodynamics of stretched rubber, a function of speed?
By stretching a rubber band slowly and then slowly releasing it can we minimize the energy lost, (minimize the change in entropy?)? If so should a hysteresis curve be a function of the rate at which...
View ArticleHeat Engine Question
Hi, I am trying to figure out heat engines. I don't understand why heat from a hot reservoir MUST exhaust heat into a cold reservoir. How does that satisfy the second law of thermodynamics? Why can't...
View ArticleFlux density in a coil?
Hello, I am looking into magnetic flux density in coils can anyone tell me if there is a general equation that equates flux density to the electric current, the coil's dimensions and number of turns?...
View ArticleHow cyclic coordinates affect the dimension of the cotangent manifold
Our professor's notes say that "In general, in Hamiltonian dynamics a constant of motion will reduce the dimension of the phase space by two dimensions, not just one as it does in Lagrangian dynamics."...
View ArticleElectromagnetic energy of a long wire
When we have a current in a long wire, what is the kind of total energy of the system? We do have an electric field inside the wire and a magnetic field outside it. I think the electric field has an...
View ArticleNonlinear Optics Book
Hi, I'm an electrical engineering student starting research in nonlinear optics, and I'd like some good books to do with nonlinear optics. I'm looking for book similar in style to Nonlinear Optics by...
View ArticleStream function/velocity potential in fluid mechanics
Hi! When you are calculating ##\psi## or ##\phi## from the horizontal or vertical velocity components of a fluid's velocity, you end up with a constant ##C## carried along with the function. In my...
View ArticleClik here to view.
Water Pressure
Hi, I am working on this water pressure problem, given: v_A = 2.0 [itex]\frac{m}{s}[/itex] gauge pressure_A = 50 kPa the view is from above, no height changes find: gauge pressure @ B so,...
View ArticleWhy is electric charge quantized?
What is the mainstream answer? And why is asking if the electric charge is quantized important? What does it mean to have charge that is not quantized?
View Article