Temperature and vacuum
The third law of thermodynamics implies there can be no vacuum. But, wouldn't that imply that there always has to be at least one particle within an arbitrarily defined box? Can there be empty space?...
View Articleorbit of figure eight 3 or more bodies
If I wanted to set up some initial conditions for a 3 body figure eight orbit, what would I have to set the position and velocity vectors? Say I have three vector inputs: initial position <x,y>...
View ArticleMoment of Inertia
So we just learned about moment of inertia in my first year physics class, and how to calculate it. Though I do know how to calculate the moment of inertia of an object, I don't really know what it is....
View ArticleLight takes the path of most time elapsed?
Hi, I'm sorry if this is the wrong section. My Dad keeps telling me that light takes the path of most time elapsed between two points, and he remembers hearing this because it's counter intuitive. I'm...
View ArticleEuler-Lagrange equations and symmetries
I'm hoping this is a really simple question, but I can't seem to find a definitive answer anywhere! If the action is invariant under some symmetry transformation, do the equations of motion need to be...
View ArticleDiscovery : A new source of renewable energy
Every object hanging on a string (like the simple pendulum) will rotate either clockwise or counterclockwise according to the place where it is ,the force which makes this rotation appears in...
View ArticleCharge attraction
Hi I googled why different charges attrack each other and I found severel answer but I guess this answers are not true because there is no info about in wikipedia or there is no mathematicaal...
View ArticleCharge Interaction
Hi I googled why different charges attrack each other and I found severel answer but I guess this answers are not true because there is no info about in wikipedia or there is no mathematicaal...
View ArticleA subtle question on restoring force in SHM
Hello, A was just helping my younger brother review some mechanics when I tried to explain how friction will cause the oscillations to eventually die out as the frequency keeps decreasing. So while...
View ArticleElectric induction
Hi, I have been told that you take say a metal board and another board (both endless and paralell) leads to the following effect: The electrons are more or less freel in motion, they move to the...
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"Summing over spins" in Ising model.
I don't understand this concept very well. Is it like taking the energy each possible configuration and adding them together? For example, if we had a 2D lattice gas and wanted to sum over the "white"...
View ArticleHow is - (gravitational) potential energy and free fall compatible?
I was having a few problems with Negative gravitational potential energy, I wasn't able to put my finger on why because it worked so well with everything else I had learned. I tried to say it made...
View ArticleThe magnetic field of a spinning spherical shell of uniform charge
In chapter 5, magnetostatics, of Griffiths' Introduction to Electrodynamics (third edition), there's a problem in the back of the chapter that asks you to calculate the force of attraction between the...
View Articleangular acceleration x radius= Acceleration of center of mass ?
For a rotating body, (angular acceleration x radius)= Acceleration of center of mass ? But a rotating body can have angular acc. even if it is not translating. what is wrong?
View Articleresistivity of a metal at melting point
Hello, I am wondering if the resistivity of a metal will increase or decrease beyond melting relative to the solid state. I think since the lattice structure of the metal is destroyed upon melting, the...
View ArticleRelaxation in classical systems
Dear all, I'd like to specify meaning othe relaxation phenomenon on example in some classical system. For example in Wiki I found example of dampled oscilator where the relaxation time ( the time is...
View ArticleConservation of ang. momentum for paths reaching a rotation axis
Hey everyone. My question is the following: if we had the trajectory of a particle eventually reaching a point of a rotation axis [itex] \vec{u} [/itex] ((take that as being the z-axis for convenience)...
View Articleinductance of a partially filled solenoid
Dear all, I am trying to calculate the inductance increase of a small ferrite rod placed in the middle of a solenoid. Let the magnetic field be considered constant, as the solenoid is long and wide...
View ArticleCenter of gravity & moment of inertia
Dear forum, while standing, spreading your legs helps your stability because you have a wider base. but doesn't spreading your legs lowers your center of gravity, thus shortening the distance (r) from...
View ArticleFree Fall of Objects Considering the Acelleration of the Planet
Dear members, My name is Gilberto F. A. and I would like to ask your help regarding a topic in Gravitation. I have formal education in engineering and recently, as part of an attempt to refresh my...
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