Potential difference
If a battery has 6V of voltage, this means that P+ P = 6V or that P P+ = 6V ? Being: P+ = electric potential of the positive pole P = electric potential of the negative pole
View ArticleCar getting struck by lightning
As we all know, if a car happens to be struck by lightning its passengers will probably be safe. The usual explanation is that the tires of the car are insulators. The actual reason, as E&M...
View ArticleMaximizing Momentum for a Rocket
The concept of a problem is that if rockets continue to jettison fuel, at some point they will get a very small momentum because their mas will be so small. (Bit of a silly problem, there's a lot of...
View ArticleElectrical breakdown
What's the mechanism behind things like sparks, lightning, St. Elmo's fire, etc.? I've heard two different explanations, both of which seem reasonable: 1) Stray electrons are accelerated by the...
View Articlepredicting momentum change
If we know the initial momentum of particles a and b (mass a and b, initial velocity of a and b), is it possible knowing the momentum after the collision without observing the velocity of two...
View ArticleIdeal electrical elements
A ideial voltage source has: v = v i = ? R = 0 L = ? C = ? ideal current source: v = ? i = i R = 0 L = ? C = ? ideal resistor: v = R i i = 1/R v R = R L = ? C = ? ideal inductor: v = L i/t i = 1/L vt R...
View ArticleCoulomb term in Potential of ions in a Penning Trap,Green's Function
How do you write out the potential of an ion in a Penning trap? Specifically, how does the inter-ionic Coulomb interaction come to be written as a Green's function? I found it here :...
View ArticleElectric Field in a Conductor
I have read that in a charged conductor, all the charge is located at the surface of the conductor and the Electric Field inside the conductor is zero. Suppose we have a conductive sphere with charge Q...
View ArticleInsulating box in a lightning storm
This question is a variation on another question I asked recently. Suppose you were in a box made from a perfectly insulating material, and a thunderstorm was raging all around you. Would the box offer...
View Article2D Bending Plate
This is sort of statics, but this came up in my physics class before. You have a plate, supported only in the middle by a simple support. So, this beam is balanced on the support, and is bending under...
View ArticleCentripetal vs Radial acceleration
I am reading introductory physics from Serway. Where they say if [tex] a_r [/tex] is radial acceleration and [tex] a_c [/tex] is centripetal acceleration then [tex] a_c = v^2/r [/tex] and [tex] a_r =...
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ODE for RLC circuit + sources
The equation for this physical model is: And for this is: But and if now I add a source of current in those schemes, the ODE changes? Attached Images x.PNG (3.6 KB) y.PNG (3.7 KB)
View ArticleDerivation of Kinetic energy formula and energy principle
Hi all, Here is the derivation of kinetic energy from Work: W = ∫Fds From the second law of motion F = dp/dt, which is equal to mdv/dt, so: W = m∫dvdx/dt which = m∫dv x v because dx/dt = v Therefore W...
View ArticleDipole and electric field gradient
I'm developing a classical model of a dipolar ion in an external electric field. It consists of two charges ##\delta_+## and ##\delta_-##, located at a fixed distance from each other. For the special...
View ArticleHow do laser interferometers measure distances greater than 1wavelengt
Hi, My question is how do do laser interferometers measure distances of more than one wavelength? I know they rely on phase difference to calculate distances but phases only differ at 180 degrees at...
View ArticleI don't understand the ''definition/law'' aspect of Newton's laws.
Hello everyone, it's been a while since I've been introduced to Newton's laws for the first time. Yesterday I've been reading the Feynman lectures vol 1, where Feynman makes a remark about Newton's...
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Superpostion theorem
I'm trying solve this scheme: but not with the ideia of solve it but yes with the ideia of understand the dynamic of the thing... aftwer watch this video: https://www.youtube.com/watch?v=x4qdec6kH1Q...
View Article4th Class Levers?
I'll assume that we all know of 1st, 2nd and 3rd Class Levers. Years ago I saw a brief remark in a magazine that I was browsing at the supermarket. It said that there was an obscure "4th Class...
View ArticleWhat could happen after maximum entropy is reached if...
When: - Vacuum had an absolute mass, relatively limiting expension of all universal matter - Newton's second law could be overridden or negated - [Anything else I couldn't think of]
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