Help with Godstein Chapter 3
This is a question to those who have the 3rd edition at their disposal. Where do 3.45 and 3.46 come from? I understood everything he said before that...
View ArticleTime-independence of original coordinates in canonical transform
I am going through my professors notes on generating functions. I come across the following equation: [tex]\frac{\partial}{\partial t} \frac{\partial F}{\partial \xi^k} = \frac{\partial}{\partial t}...
View ArticleCan Gravitational energy be derived from First Law of Thermodynamics?
I'm not sure if I'm right .. Here's my thought: 1. The First Law of Thermodynamics is the only single law which could derive energy formula. Furthermore, we can't use Newton's law to derive Kinetic...
View Articlequestion regarding underwater pressure
Hi, I am having some argument with my friend over the following elementary physics problem: Assume there is a pressure sensor located at position C underwater and deep enough, and assume also the water...
View ArticleWhat is the physical difference between compression waves and longitud
Hello, this is my first post on this forum so nice to be here, and I'll be very appreciative of any responses. My background is in acoustics, and hence my question is relevant to vibration propagation....
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Liquid helium and curved piston
It's a theoretical study. Like the image showing, the curved piston move in container and need energy for that. In the same time, another piston move up and recover energy. The pressure inside...
View ArticleForced Oscillations
Hi, why is it that as the frequency of the driver decreases below the natural frequency of the oscillator it reaches a fixed amplitude when the external frequency is zero whereas whenever you go to the...
View ArticleSign of acceleration due to gravity doubt
I have a question, according to rules for the sign of x and y-acceleration; when I should use the negative sign for gravity (g) in a problem, because it's confusing since I've seen that according to my...
View ArticleWork done
I've always thought of work done as being calculated by something like ∫F.dx whenever a force acts on a moving body. Another way of writing this ∫F.vdt. The non integral form of this equation (W = Fv)...
View ArticleChange in kinetic energy between reference frames
I was trying to do some studying regarding the definitions of energy, and I've hit a road block. I know that since velocity is frame-dependent, an object's kinetic energy as observed in two different...
View ArticleCentrifugal force
According to the wikipedia page, when given an angular velocity, centrifugal force increases with radius. I always thought the larger the radius, the smaller the centrifugal force. I think I'm...
View Articlecooling between chambers
I have a practical problem that I am trying to solve regarding using air chambers. I hope someone can help me with the problem. I have two air chambers connected by a tubing and a valve. One is pumped...
View ArticleHow do the Maxwell equations transform under a time reversal?
Guys, Let me ask you the silliest question of the year. I am looking at the Maxwell equations in their standard form. No 4-dim potential A, no Faraday tensor F, no mentioning of special relativity -...
View ArticleX-ray's can cause demagnetization?
I found this my mistake, it's amazing how for a very short period of time, Xray(and other lasers) can demagnetize a ferromagnets. This is still under research, but how can this be? Can anyone share...
View ArticleSimple anharmonic motion
Dear all, I've already known the basic forms and general equations which describes harmonic motion in case of description of simple oscilation system by means of Hooke laws. Could you provide me with...
View Articlehow to calculate the magnetic field generated by accelerating charges?
my guess was Jefimenko's equations could be used, am i right? also are there any other relevant equations or methods? also what does the current density derivative in the equation (in terms of the...
View ArticleHelp with understanding an experiment with masses on a spring
We did an experiment not so long ago that involved suspending masses on a spring and not knowing much about the background to what was found is hindering my ability to fully grasp the results. The...
View ArticleFree fall and air resistance
My textbook source is: Fundamentals of Physics, 6th edition, by Halliday, Resnick, Walker According to Newton's well known 2nd Law of Motion: Fnet = ma In chapter 2, in the case of free fall, the Fgrav...
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kittel: possible states of magnetic
I do not understand the attached picture excerpt from Kittel Thermal Physics (first sentence up to 'eqn' (7) ). I would expect the moments to go down in increments of one, not two. I think the...
View ArticleFrom Poynting vector to EM wave
After reading Griffiths' book, I find the explanation from poynting vector to sinusodial EM wave pretty blurred. EM wave has two requirements. 1. E / B = c 2. E and B are sinusodial How could we ensure...
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