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Out of balance rotating system
Figure Q4. illustrates a rotor assembly with out-of-balance rotor discs in planes A, B and C. The out-of-balance mass x radius products in planes A and C are as indicated in the figure. The...
View ArticleResistance in circuits with transformers
I am starting to learn about transformers, and know the basics: they use electromagnetic induction to induce a current in a secondary coil, and the voltage and amperage of that second coil are...
View ArticleNet external work
Quick question about net external work Got a block (A) attach to Spring which attach to a Wall Hand pushes A toward the wall which compress the Spring So hand is doing positive work on A, W = F*D, work...
View ArticleAC theory help needed
Hey, so I've just started learning about AC theory. I understand the reactance part of it, both capacitive and inductive. Although there are a few things I need to clear up. If there's a resistor,...
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Moment of Inertia problem
Does anyone know how to solve the problem 1.b on page 101 in Landau and Lifshitz, Mechanics? Please note that my attempt is shown in the attachement I am stuck after this step. Attached Images...
View ArticleIntuitive, real-world explanation of displacement current?
I know and fully understand the mathematical definition of it. But what's the physical explanation? Is it something like "preservation of current" or something?
View ArticleTorque has dimensions of energy
I just noticed that torque has dimensions of energy! What does that mean?
View ArticleConservation of angular momentum
Imagine a body that is attached to a massless string and then rotated in such a manner that no external forces like gravity acts on the body in tangential direction. The body now has the angular...
View ArticleEnthalpy of an ideal gas
I've read on Wikipedia that the enthalpy of an ideal gas does not depend on pressure (http://en.wikipedia.org/wiki/Enthalpy: Quote: Quote by WikiTheGreat Enthalpies of ideal gases and incompressible...
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Heron fountain antics
Let me start off by saying I know it is not perpetual motion. I understand this. I was thinking about the fountain and was wondering if this arrangement would allow you to equalize the compartments and...
View ArticleCharging capacitor by another capacitor
Hi, Consider a charged capacitor connected to a an empty capacitor. The charged capacitor starts to discharge while the empty capacitor starts charging. The whole process finishes when the two...
View ArticleInductor opposing change in current.
Hello, I'm wondering, if you have an inductor and resistor that has the switch open, so current is zero. Then you turn on the switch, the inductor is going to resist this change, it wants to be zero,...
View ArticleFree expansion of a Van der Waals gas, physical explanation
Hello! Today I've learned that when a Van der Waals gas undergoes a free expansion, it cools down a bit. :bugeye: This is in contrast with the ideal gas in which case since it does no work and since...
View ArticleBuilding an electromagnet, need help
I've had some bad trouble trying to create an electromagnet, so I've come here in hopes of help. Basically, I need to create an electromagnet strong enough to lift 2kg of weight. Because I don't know...
View ArticleRadio lattice interactions
So mobile devices use radio waves so I had this thought that if there was evidence linking radio waves with changing organic tissue structure is the evidence that radio waves can be used to change the...
View ArticleWhy are resistors useful?
I don't understand why we use resistors at all. I've read that they cause a voltage drop and decrease the flow of electrons (current). Why is this useful? If we want to decrease the current, why not...
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[Hanging/Sliding Chain Problem] Confusion in Normal Force
This is a very basic problem which you all must have seen somewhere. But recently an itching doubt has come up to me regarding this problem. Problem: A chain lies on a table with some part of it...
View ArticleAbout accellerating charges...
So we know that an accellerating charge will emit EM waves. Consider putting a voltage through a circular wire. Electrons are travelling in the wire with constant speed but their velocity is changing...
View ArticleQuestions on pressure and non-ideal gases
Hi! I have two questions. First, how do I calculate the pressure of a non-ideal gas if I know volume, temperature and the number of moles? The gas in question is water vapor. I suspect a constant for...
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Electric Potential in circuits
Hi, I'm just starting to study circuits, and there's a thing I don't understand about electric potential. I was under the impression that as a charge moves through the circuit from the high potential...
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