Conservation energy to find escape velocity
Guy, i have a problem. When we use conservation energy to find the escape velocity, ie the root of potentiality is unlimited, why we don't compute the velocity of earth? We knew the earth rotated its...
View ArticleSubstituting differentials in physics integrals.
Today I tried to show that rotational kinetic energy was equivalent to standard translational kinetic energy. So I started with kinetic energy, T = ∫dT. Then, because T=1/2mv^2, I substituted...
View Articlehelp me understand how deformations work
Ok, umm these may sound like dumb questions, and im sorry but here goes. (I think i have a lot of misconceptions) 1. If I push myself against a wall and exert a constant force, the wall will exert a...
View ArticleCollision of falling and thrown upward balls
Hi, I am wondering if total momentum of the system is conserved in this case. Our system is consisted of two balls: one is falling vertically down to ground, another is thrown vertically up, so they...
View ArticleHow to understand "momentum is the generator of translation" ?
"As it is known from classical mechanics, the momentum is the generator of translation", it is from WIKI, (http://en.wikipedia.org/wiki/Momentum_operator) I don't understand its meaning. [itex] T(ε)...
View ArticleThermo - PV work and mechanical work
Hello, I`m a bit confused about PV work. Here is the situation I am facing. δw = P dV and dw = F dx δw is an inexact differential, because it's path dependent. I read some articles that equal δw with...
View ArticleUnderstanding how to set up integrals for inertia
Hello, and thank you in advanced for this. I am having trouble with setting up most if not all of my integrals when I am trying to find the elements of an inertia tensor. What would I do if i need to...
View ArticleDiffraction orders
Hi, I was wondering how you can calculate the intensity of light produced by diffraction orders. If say a laser was incident on a diffraction grating and this split the zeroth and +-1 orders what...
View ArticleVector potential components in small loop antenna
Consider a small, thin loop in the [itex](x,y)[/itex] plane centered in the origin and with radius [itex]a[/itex]. We are interested in the vector potential [itex]\mathbf{A}[/itex] generated by the...
View ArticleFrustrated total internal reflection: Where does energy come from?
Hi, When we have total internal reflection of light at the boundary of an optically dense to an optically thinner medium, one can show that the component of the Poynting vector perpendicular to the...
View Articleinertial forces
it was mentioned in another thread that only inertial forces are frame dependent or relative. what is an inertial force? what are the differences between inertial and non-inertial forces? and most...
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Equilibirum concentration in thermodynamics
Are any of you here comfortable with thermodynamic calculations for heterophase fluctuations? Then please help me understand an important bit in my book (attached) I am doing a project on nucleation,...
View ArticleWhy do all objects fall with the same acceleration regardless of mass?
I am well aware that objects of varying masses, shapes, and surface areas will fall at different speeds and accelerations in an environment with a gas in the way such as air due to air resistance. Why...
View ArticlePertubations To Helmholtz Equation
Consider the Helmholtz Equations with a perturbation p(r) [gradient^2 + p(r) + omega^2/c(r)^2 ]u(r,w) = 0 Does anyone know where I can find resources to the solutions/discussion of this equation? I can...
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Energy conservation paradox for constrained mass
Consider the following setup (see illustration above): a mass m is connected to a circular section of a rail by means of a rod (with negligible mass) of length r, where r is the radius of the rail....
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Maxwell-Boltzmann Distribution and Probability
In the book 'Macroscopic and Statistical Thermodynamics' they derived the Maxwell-Boltzmann distribution by maximizing entropy using lagrangian multipliers with constants ##\alpha## and ##\beta##. The...
View ArticleWhat does positive U mean?
If a group of point charges as a whole, has positive potential energy, what does that mean? What will happen if the point charges are free to move?
View ArticleNewton's shell theorem & Nuclear Fusion
I have a problem reconciling something. According to Newton's shell theorem, at any point within a solid sphere, for the purposes of calculating the gravitational force exerted on you, the mass that is...
View ArticleDoppler effect, source and receiver in different media
Hello, For convenience, we can say that a submarine at some depth in sea emits sound wave which refracts from the surface of the sea and is caught by a helicopter at some height above the sea. If we...
View ArticleWhy is the natural frequency of a column at the buckling load?
So apparently the natural frequency is zero for uniform column with axial load when P is equal to the critical buckling load. Could anyone please explain theoretically why this is the case.
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