Resonance in a tube
Why do we assume that an antinode is present at open end of a tube? Can a node be possible at open end? Thank you in advanced.
View ArticleCar mass and maximal speed when cornering
Hello, I would really appreciate if someone helped me to figure this out. Suppose we have got a car A and car B. They both have got the same body (aerodynamics), tires, center of mass, the only...
View ArticleDiv B = 0? I don't get it
The divergence of a vector field tells us how many field lines goes into a volume element in relation to how many goes out. So if div B = 0 there should be the same amount of magnetic field lines going...
View ArticleElectric field produced by a magnet
Hello, I was just wondering how is it that a steady magnetic flux (stationary magnetic field) is capable of inducing a current in super conductor, as in the Meissner effect, where as a changing...
View ArticleUnderstanding the centrifugal force
I'm learning about mechanics in noninertial frames and I'd like to clarify the apparent centrifugal force. To set things straight, Centrifugal force = Fcf = m(Ω×r)×Ω where Ω×r is the instaneous...
View ArticleAngular Acceleration problem
Hi, thanks for taking a look! A toy train rolls around a horizontal 1.4-m-diameter track. The coefficient of rolling friction is 0.12. (a) What is the magnitude of the train's angular acceleration...
View ArticleMind-spinner 1: When (do/don't) action/reaction force pairs cancel out?
Hello to everyone! This is my first post. I have some basic knowledge in physics back from high-school, but since I decided now to pursue a degree in physics, I am starting from the bottom to get a...
View ArticleEnergy of a dielectric
I've examined and re-examined the proof that the energy density of a linear dielectric is [itex]u=\frac{1}{2}\mathbf{D}\cdot\mathbf{E}[/itex], but I still don't understand it. I'll rewrite it here and...
View ArticleMeasures of the intensity of electromagnetic radiation
I've always struggled with the commonly used measures of the intensity of electromagnetic radiation and it's catching up to me lately. Suppose [itex]\bar{P}(R,\phi,\theta)[/itex] is the Poynting vector...
View ArticleDeriving relation between angular momentum reduction by torque
Friction causes a torque that opposes angular momentum. It gets reduced. how can we derive a relation connecting these. friction starts with maximum and becomes zero. angular velocity and its...
View ArticleHow can we measure entropy using experiments.
A friend asks me this. If considering the equation: [itex]∫\frac{dQ}{T}[/itex], then it is technically feasible to work out some forms of expressions with measurable physical quantities like...
View ArticleKibble book exercise about conservative forces
Kibble book exercise 1, chapter 3. It is the following: Find which of the following forces are conservative, and, for those that are conservative, determine the corresponding potential energy function...
View ArticlePolarization of Electromagnetic wave
Dear friends i know that a wave is linearly polarized if its components have a phase difference of n*∏ and is circularly polarized if phase difference is n*∏/2. But what if phase difference is neither...
View ArticleVelocity Space Distribution Function
I need some guidance or where or how to learn the mathematics for velocity-phase space integrals that appear in Maxwellian distributions. I'm an Engineer in Electronics and Communications, taking an...
View Articletsiolkovsky's rocket equation question
How would the equation look if instead of knowing the effective exhaust velocity we knew the force the exhaust was exerting on the rocket. The equation is: [tex] \Delta V = v_e * ln(\dfrac{m_0}{m_1})...
View Article(Average) Kinetic Energy of Molecules
I'm confused with this topic. However, I think I know a bit. There's something to do with the temperature and it affects the energy of the molecules. Can someone help?
View ArticleEquilibrium with Lagrangians
So let's say we have a mechanical system described by some Lagrangian [itex]L=L(q_i,\dot{q}_i)[/itex], where the qi's are the generalized coordinates of the system. Does the condition...
View ArticleElasticity (understanding elasticity from stress strain curve)
Hello .. I have problem understanding how to decide which material is more elastic based on stress strain curve.. my understanding is as follows 1)if a material has big youngs modulus.. then it is more...
View ArticleEasy problem with heat transfer from surrounding air to water tank
Hi! Im doing some measures on a closed water tank with the water temperature 14C and surrounding air with temperature of 20C. I want to know how much heat transfer there is between the surrounding air...
View ArticleDielectric Vs. Resistor
Hi, Do material posses both dielectric as well as resistance properties? I imagine that when there is a difference in potential across a volume of some material, some current will flow (I=V/R <--...
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