Lagrangian for the Kepler Problem
In a two-body solution ( Kepler Problem) how do you find the Lagrangian, L, if the position vector is: [tex]x = (v_x * t + x_0, v_y * t + y_0, v_z * t + z_0)[/tex] Action from Wikipedia is: [tex]S =...
View ArticleUnderstanding the MC flux limiter
I'm reading through these notes on numerical hydrodynamics. On pg17, they introduce the monotonized central difference flux limiter, which looks something like [tex]\frac{\partial~a}{\partial~x}|_i =...
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Best algorithm for an object that moves across an area
Imagine a rectangular plane with dimensions X and Y. On that plane is a car. The car is about Z meters wide (the front bumper width, or up-down width in the image below). The car travels at a velocity...
View Articledetermine air conditioning cooling time
how can i calculate the require time for an air-conditioning unit to cool from 30 degree celcius to 22 degree celcius? others parameter can be ignore, i would like to know the formula used and the...
View ArticleEM waves: energy and power related to frequency
Hello, I was reading articles about EMR and health and I realized I never got how "output power" is related to frequency. Let's talk about energy, the rule is: the higher the frequency (shorter...
View ArticleKinetic to Static Friction
Are there any fans of truck or tractor pulls out there? I am trying to understand what is happening to the coefficient of friction as the sled transitions from kinetic friction back to static friction....
View ArticleSimple Fluid mechanics question, Need Help
I've been solving fluid mechanics problems and i encountered two problems that made no sense to me. Both problems that ask about the force done by water on a VERTICAL wall under the level of water. One...
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Fluid mechanics problem, need explanation please
Hi please check the highlighted question in the attachment and the solution and see the problem, i need help please. I have two questions about it: 1- why didn't we take the plug as a vertical wall and...
View Articlestatic pressure in Air Handling Unit
what will happen if static pressure in supply duct is higher than the fan compartment in AHU?? or vice-versa thanks
View ArticleAbout Taylor & Wheeler 3-1 practice problem
Hi, I'm an amateur italian physics addict, so please sorry for my english, eventually. I'm reading carefully the Taylor & Wheeler 2nd edition, and I'm trying to do all the problems before jumping...
View ArticleA decent "k" value for newton's law of cooling for water?
Recently I've been trying to cool some water to a specific temperature from boiling. It doesn't have to be super accurate (within about 5° degrees Fahrenheit or 2° Celsius) but the only thermometer I...
View ArticleWould anything going the speed of light kill you and would fermions?
I had to cut the title short but would anything going the speed of light kill you even though it is impossible? I know that light is going the speed won't kill you but would it count? Because since...
View ArticleCurious about gravitational sluing detail
Let's say a big rock is headed toward a small moon, impelled only by existing momentum and gravitational pull. The rock is not rotating or tumbling at all, leastwise not in relation to the local...
View ArticleBasic question about kinetic energy and momentum
Hi, I'm learning about momentum and kinetic energy and I wanted to know if the following relationships are true. I think they are true, but I am not sure: If kinetic energy goes down and mass stays...
View ArticleSimple Magnification Question
My question is simple but i can't seem to find a straight answer. Can a single lens, a biconvex lens let's say, have a fixed magnification.I know that magnification is a factor of focal length, and...
View ArticleDoppler Effect
hi i just wanna ask about the formula of Doppler Effect . The speeds of the listener VL and the source Vs are relative to the ground, source, or listener ?
View ArticlePressure, energy density, and power of a fluid flow
I've read that you can view static pressure of a fluid as energy density, which makes sense to me. I've also seen that the power of a fluid flow can be calculated by multiplying the pressure by the...
View ArticleQuick question on coupled pendulum kinetic energy
I have found that the kinetic energy term for each mass on a coupled (by a spring) pendulum has no [itex]\dot{y}[/itex] terms, as in the the masses do not move in the y direction at all. What am I...
View ArticleQuestion about Maxwell's equations
My question is essentially about Ampere's law. I went the long way about and evaluated the curl of the magnetic field, [itex]\vec{B}[/itex], of a point charge, q, located at position...
View ArticleBernoulli's Equation
why is when working with Bernoulli equation the absolute pressure that we are NOT looking for has a gauge pressure = 0 and only atmospheric pressure while the one we are looking for has both? is this a...
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