Fluid inside a sphere
Hi all! Imagine you have an ideal sphere (made of steel or plastics). Then fill it completely with some fluid, e.g. water. Then rotate it very fast. What happens to a fluid inside? I suppose that it...
View Articlework done by ideal gas
Hi all, I was wondering if I am having a definition problem on mechanical work. Since dW = -PdV (as I was told in class), is it correct to say the pressure is fixed with W = -PV, since dW = d(PV) =...
View ArticlePV work: differential vs instantaneous
Hello, I am having a conceptual difficulty understanding the following scenario Suppose you has a tank with a piston and some gas. In the first situation, there is some weight on the piston holding it...
View ArticleAn exact solution for the Navier-Stokes?
Quote: In early January 2014 the scientific world had spread sensational news. Press office of the Eurasian National University named after Gumilev in Almaty, said the director of the mathematical...
View ArticleStanding Waves
Do all frequencies produce standing waves or just the harmonics? My physics textbook stated that standing waves are form when two wave trains with equal amplitude and frequency meet each other in...
View ArticleComplete Removal of Matter from Space
What is left if all matter and energy is removed from a particular region in space? For example, say I completely remove all of the matter and energy from a region of the air in front of me (also...
View ArticleLight Polarization in 2D
Hello i wasn't sure if to ask this in here or in homework! I stumbled upon an assignment to build the model of photon gas in 2D space. in the answer it was stated that the light have 2 polarization...
View Articlewhy doesn't gravity speed up light?
We know that gravity speeds up a body, like a meteor which enters the earth gets constantly speeded up by earth's gravity. And from relativity we know that light bends near a massive body because...
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A Scalar Equation of Motion
In classical mechanics, this thread presents a scalar equation of motion, which can be applied in any reference frame (rotating or non-rotating) (inertial or non-inertial) without the necessity of...
View ArticleElastic modulus
I'm learning about Hooke's law and modulus of elasticity (also known as youngs modulus) but it seems I am being taught it differently in maths and physics. In maths I am taught that T=λx/l and λ is the...
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Infinitely stretchable elastic band
Imagine an infinitely stretchable elastic band where one end is attached to a vertical wall and the other on a horse, as shown in figure. On the elastic band, very close to the wall, there is a snail....
View ArticleGravitational pull on an object
How much does gravitational pull on an object decrease if the distance is increased 10 fold for example? If planet x is stationary and part of a binary star system where star y is 1 AU away from it and...
View ArticleForce to Lorentz Force
Greetings, I am trying to to show that the force in this form: [itex]\dot{P}=e(\vec{∇}\vec{A})\vec{\dot{x}}-e\vec{∇}\phi[/itex] Is equal to the lorentz force. I have been trying the approach of some...
View ArticleCircular motion
I have seen the derivation of the centripetal acceleration formula a=v^2/r by saying r= rcosθi+isinθj=rcosωti+rsinωtj and differentiating twice. Since ω is constant we get a=-ω[itex]^{2}[/itex]r. I've...
View ArticleHeat Transfer
Hello Everyone, The question I am about to pose concerns something I may possibly already have an answer; however, I would like to proceed with posing the query, that I might solidify my understanding....
View ArticleBattery Output
If you study a DC signal under an appropriate scope, you can see the switching transitions ; a pwm signal. But if you examine a battery, no matter how high temporal resolution you reach, you see a dc...
View ArticleTransformers & Phase Difference
Hi, I'm trying to figure out what phase differences take place with an ideal transformer. This is what I have figured out so far: If you apply an AC current to the primary coil then you will get an...
View ArticleOptics: Whispering gallery modes in large systems
While reading about whispering gallery modes, I have learned that whispering gallery modes can be seen for "microscopic spheres or toruses" -Wikipedia- , But can they practically be observed in...
View Articleyoung fringes formula
Hi all I am looking for the intensity of the fringes on the screen behind two slits with a given width. I thought it would be easy to find with google but no.
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