Euler's equation for one-dimensional flow (Landau Lifshitz)
One page 5 in Landau & Lifshitz Fluid Mechanics (2nd edition), the authors pose the following problem: Quote: Write down the equations for one-dimensional motion of an ideal fluid in terms of the...
View Articleeffects of size and speed on model airplane crashes
I am looking for an equation that correlates material failure and collision speed; so that I can better understand the effects of size and speed on model airplane crashes. Is there an equation that...
View ArticleEnergy conservation of a rod in free space
Hey everyone, A meager pea brain (me) is in need of some help from you fine physics gentlemen. This is a concept I've spend a lot of time pondering on (more than I would like to admit). Imagine a rod...
View ArticlePoynting vector and intensity in scalar diffraction theory
The power density of an electromagnetic wave is proportional to the absolute square of the electric field |E|^2 (assuming a plane wave). Here, E is a vector so the absolute square involves all three of...
View ArticlePlanar motion in central forces.
I understand that in a two body problem under central force, corresponding to a potential V(r)(assume one body is massive compared to the other so that its motion is negligible), conservation of...
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Tension in rope when the system is accelerating
hey, I'm currently going through a mechanics course on edx.org . And part of last's week homework was this problem. well okay I don't know how to add images so I'm gonna try my best to describe it....
View ArticleCalculating Thermo Properties of Water in Excel
Hi - I am currently working on a paper verifying some thermal hydraulic code against experimental test data for subcooled water subchannel flow. I have close to 1000 points in excel all listed with T...
View ArticleWhy does this Lagrangian seem "asymmetric"?
I got this Lagrangian on the exam and it just seems weird to me: L = [itex]\frac{m}{2}[/itex](ẋ²+ẏ²) – eBẋy What I mean by "asymmetric" is that it doesn't seem to behave in a same way on x as on y,...
View ArticleChanging speed of light
If the speed of light is changing, does this mean that the permattivity and/or permeability are dynamically changing quantities? are these "constants" derivable yet or are they still only...
View ArticleCan light travels without electromagnetic field ?
Can light travels without electromagnetic field ? Thanks
View ArticleHamiltonian for classical harmonic oscillator
I am working through Leonard Susskinds 'the theoretical minimum' and one of the exercises is to show that H=ω/2(p^2+q^2). The given equations are H=1/2mq(dot)^2 + k/2q^2, mq(dot)=p and ω^2=k/m. q is a...
View ArticleNewton's 3rd law query
I notice on this page at Rice University that regarding Newton's 3rd law it says that... Quote: The rocket's action is to push down on the ground with the force of its powerful engines, and the...
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Optimizing structure for toppling
Hi! everyone... I'm a building a standing frame for disabled children, the structure in elemental form is shown in picture. link to picture - https://drive.google.com/file/d/0B60...it?usp=sharing Now,...
View ArticleTensors: switching between mixed and contravariant components
I'm working on the electromagnetic stress-energy tensor and I've found this in a book by Landau-Lifshitz: [itex] T^{i}_{k} = -\frac{1}{4\pi} \frac{\partial A_{\ell}}{\partial x^{i}}...
View ArticleDirect conversion from heat to electrical energy
Hi to all. I'm looking for ways heat could be converted directly to electrical energy. I figured out some machinery out there that can convert heat to electricity by difference between temperatures,...
View Articlehow much stuff will neutralise the sun's pull on the earth
I tried to make the title as descriptive as I could without being overly long. Anyway, I've been trying to work this out but I'm having some difficulty. We all know the strength of the electromagnetic...
View ArticleRayleigh Dissipation function for aerodynamic Drag
Hi I'm trying to model the drag effects in using Lagrange Mechanics and trying to include the effects of aerodynamic drag. I've read up on the Rayleigh Dissipation functions in Greenwood's "Advanced...
View ArticleSurface tension object targeted
To what I know, surface tension is a force that appear at the interface between 2 bulk phases, and is parallel to that interface. Let consider a bulk of a fluid in the air. In the bulk of a fluid at...
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Capillary action meniscus height in a tube fitted inside another tube?
Hello, I was thinking about how would capillary action change in a tube (classic example) and in a tube fitted inside another tube (considering water as the liquid involved). This is no homework...
View Articlewine glass sound physics behind
when you slide your thinger around the rim of glass it produces resonance the matter which vibrates is a glass, not air, right? i understand that when ou hit a glass once it produces sound as by...
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