Is it possible to have a magnetic diode?
I wonder: do there exist "magnetic semiconductors" and magnetic diodes and transistors? Normal electrical semiconductors rely on the fact that there are positive and negative charge carriers. Magnetism...
View ArticleClik here to view.
Motion along a three-dimensional plane
Hi, I am working on an example that demonstrates Newtons laws in 3-dimensions (this is NOT homework). In my example I focus on incline (frictionless) motion, which can be represented as below in...
View ArticleBibliographical reference needed
I'm interested in a serious discussion (at the level of Arnold's mechanics text) about the alleged connection between Boltzmann's H theorem and Poincaré's theorem (rumor has it Boltzmann was pretty...
View ArticleIdeal Gases under Adiabatic Compression
I'm having trouble understanding what happens to the internal energy of an ideal gas being compressed adiabatically. If DU = DQ + DW, then as we do work PdV compressing the gas, since in adiabatic...
View ArticlePower on a slope
Im trying to figure out how much power is needed to maintain a vehicles speed on a slope I found out that my car weighing in at about 2000 lbs needs 15hp to maintain 75 mph on a flat road with no wind....
View ArticleMomentum + Walking On a Boat
A 200 kg canoe lies at rest in the water, near a dock but untethered. Any friction between the canoe and the water is negligible. A 60 kg man runs along the dock toward the boat and jumps in, at...
View ArticleRC Charging
Hello Everyone, I need to solve this problem: How many seconds does it take to charge a 7.7 x 10-7 farad capacitor to 70V if it is initially uncharged, then connected to a 190V battery through a 11000...
View ArticleGravitational Constant Measurement ?
How did we measure the gravitational constant G = 2.034 x 10 ^ 17 cm ^ 2 and the Earth average density (specific gravity) p = 3.45 g / cm ^ 2 s ^ 2.
View ArticleWhat do you mean by rigid body?Can anyone tell me why rigid body does not exist?
Hello, Does anyone knows why rigid body does not exist.So in order to know its history which textbook can i refer to ???? For example to know classical mechanics properly you have to go to Newtons book...
View ArticleHow to simulate pressure in an ideal gas simulation
Hello I wrote a simple simulation of an 2D ideal gas, with elastic collisions. I wonder how should I simulate the pressure that is implemented on the particles in the box, by a piston with certain...
View Articleearth stop to turn
Hello, according to the classic physics a body subjected to an acceleration must dispers energy, the earth is subjected to a centripetal and centrifugal force so why it doesn't stop to turn ?
View Articleskydiver balloon
Why can't we fill the balloon with the lightest substance available, i.e. vacuum?
View ArticleBurnt up
Objects burn up entering earth's atmosphere. If we were to float high enough wouldn't the same thing happen? Or does` the rate of descent play a role?
View ArticleProblem in deriving an expression
Hi! In this paper: http://www.atm.ox.ac.uk/user/read/me...s/LA-notes.pdf On the bottom of page no. 25 there is written, that: \int δWdt=-\int δVdt. Why is that? Can anyone explain in to me? Thanks in...
View ArticleAngular momentum in Lagrangian Mechanics
In Newton's problem,and other central force problems in Classical Mechanics, you can get with decreasing the center of mass movement to the lagrangian: [itex]L=1/2m(r' ^2+r^2 \varphi'^2)-V(r) [/itex]...
View ArticleMoment of inertia: off-central diameter
Question for the brilliant minds around here: I'm trying to figure the amount of torque (I*a) needed to rotate a cylinder of a given mass, diameter and length around a pivot point that is off-center....
View ArticleBuilding a cyclotron - tips/ideas
Hello! I am interested in building a cyclotron. Since I doubt that I will be compotent enough to build a cyclotron right now, what are some tips that you can give me to get me started on the (long)...
View ArticleBuilding a cyclotron - tips/ideas
Hello! I am interested in building a cyclotron. Since I doubt that I will be compotent enough to build a cyclotron right now, what are some tips that you can give me to get me started on the (long)...
View ArticleClik here to view.
Sum of energy in a system like barometer
The drawing show a barometer with water inside. If I move up object with air inside I recover PV energy (P=external pressure, V=volume of object). If I want to move out object when it is at top, I need...
View ArticlePoynting theorem
I have to admit I don't really understand this theorem fully. As far as I understand it says that the work done on a volume of charge is equal to the change in the field energy inside the volume plus...
View Article