Cooling a pond with river water??
Hi all, this is kind of a basic question and I am looking for a simple formula to use to illustrate how an idea is not practical. I worked almost this exact same problem years ago in a limnology class...
View ArticleIs the position a vector???
Today I had a lecture on classical mechanics and the professor talked about vectors and how do we use them in physics to describe some physical quantities as velocity and acceleration. But he was very...
View ArticleHow to handle simultaneous particles collision in simulation?
Suppose there are 3 balls colliding at the same time. I find that the order in which I resolve collisions makes a difference in the final result, which ofcourse makes no sense. To explain and keep...
View ArticleWhat happens to cohesive forces when things break?
Cohesive forces holds stuff together, these forces being strongest in solids. However, why don't things (say, a stone) stick back together if I push them close?
View Articlegravitational potential energy near the earth
I am a bit confused about gravitational potential energy near the earth, namely the formula given by mgh. I know that potential energy is defined as U(x) = -W(x0 to x) where x0 is our chosen reference...
View ArticleDirection of Poynting vector
I have a question: when the poynting vector and energy propagation in electromagnetic waves are in the same direction and when are in different direction?
View ArticleThermodynamics Questions
Hey all, I have a question that arose out of some thermodynamics review I'm going over for an upcoming course. It relates to different properties surrounding ideal gases. There are some other various...
View ArticlePlanck's radiation law
Can anyone give me a simple proof of planck's radiation distribution law ?
View ArticleTemperature of a homogeneous land surface
Hello, I have temperature and emissivity data values for different land types (i.e. rock, vegetation etc.) of an area in form of image pixels. Because there are different land types, they show...
View ArticlePoincaré group is semi-product of translations and Lorentz-group
Hi everybody, Can somebody help me with the following proof. Show that for the Poincaré group [itex]P=T\odot L[/itex] Where [itex]T[/itex] is the group of translations and [itex]L[/itex] is the Lorentz...
View ArticleFormula for relation between pressure and volume for GAS
Hi all, I am brand new here and need some help - i hope it is the right category i am posting in. I am no expert in physics - i am working at sea as a mate on board producttankers. I would like some...
View ArticleQuestion about ohms law and non-ohmic behavior.
I recently learned that ohms law is not always obeyed. I found this surprising because I thought ohms were defined in terms of volt and amperes by the equation R=V/I. I did a little googling and found...
View ArticlePotential energy, Is energy a constant scalar value?
Hello everyone, Does everything in the universe have potential energy? I know there are two main form's of energy that are showen every day... Motion KE and potential energy and I believe all physical...
View ArticleLagrangians giving the same equations of motion
Hi, I'm trying to clear up a confusing point in the book by José and Saletan, concerning equivalent Lagrangians (in the sense that they give you the same dynamics). It is clear that if [itex] L_1 - L_2...
View ArticleWhy did my compass work perfect at the store but stop working soon as I got...
I bought a compass today. I tested it at the store, multiple times, spinning all which ways. It would always immediately spin itself around to accurately point north.. It is one of those ball compasses...
View ArticleDoes a centrifuge weigh more when it's spinning?
This may or may not be a crazy question but do centrifuges weigh more when they're spinning? Perhaps I'm misunderstanding g-force, weight and centrifugal force.
View ArticleAir compression via acceleration?
When we are sitting in our cars, and the car begins accelerating we are "pushed back" due to acceleration. Or if you have a ball in an empty vehicle, when it starts accelerating, the ball will roll to...
View Articleconceptualizing resonance.
In a mass-spring system that is driven by an external force, its displacement-time graph consists of several components. One of them is Asin(bt), where b is the driving frequency and[tex]...
View ArticleCentripetal acceleration question: car moving around banked curve
If the wheels and tires of a car are rolling without slipping or sliding when turning, the bottom of the tire is rest against the road at each instant, so the force of friction is the static friction....
View ArticleReduced mass
Will any one help me to understand the concept of reduced mass , where does it come from and its physical significance
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