Weird Definition and 469 Threads

Homework Statement Homework Equations at point C: i2 - i3 - i4 i2 = i3 + i4[/B] The Attempt at a Solution I labeled all the currents going through each resistor in the picture[/B] for loop ABC: 2000i1 = 3000i2 + 4000i3 for loop BDC: 3000i5 = 2000i4 + 4000i3 at point C: i2 - i3 - i4 i2...

I'm trying to follow the calculations in this paper. But I have a weird problem in section 2. To calculate the entanglement entropy using the Ryu-Takayanagi prescription, you have to extremize the area of a surface. So you have to use Euler-Lagrange equations for some kind of an action. The...

I was just playing with some numbers and I noticed this weird pattern. Because of the complexity of the problem I am finding it hard to describe it in words. But you can easily understand it by looking at the picture. Whenever I form a series by adding numbers in Arithmetic progression to the...

Homework Statement Two aircraft approaching an aircraft carrier are detected by radar. The first aircraft is at a horizontal distance of 34.3 km in the direction 42 deg north of east. and has altitude 2.4 km The second aircraft, at altitude 1.2 km, is at horizontal distance of 42.6 km in the...

far out !

This probably is as impossible as i think, but can an airplane have slanted wings? By this I mean, can an airplane's wings operate like a see-saw with one with angling upward, and the other going equally downward while the main body of the plane doesn't move at all. This mechanism would sort of...

Hi. I have this Bessel look-a-like DE (however it has the negative sign on the dependent variable): My attempt at a solution is by (obviously) trying to transform it into a Bessel DE by multiplying it with x2 on both sides, then it would look like the Spherical Bessel differential equation...

Hello everybody, I'm playing with a ne -ne laser And i conducted an interesting experiment I did colliding beams the type of interferometer Fabry Pero between the mirrors I put the cuvette with different substances I tried to detect changes of polarization of the laser beam with the help of a...

Homework Statement Compare two strings which represent test scores for a 20 question exam. If the student scores 15 or higher, they pass. Less than that they fail. Indicate whether a student passes or fails. Display how many answers they got right and wrong. Display which number they got wrong...

So I am an employee of my university. Last semester I was given a stipend as an undergraduate researcher. For medical reasons I couldn't pursue that stipend this semester, but now have taken a job as a math tutor. Because I transitioned from one job to the other, I was informed that HR will...

Homework Statement Find the range ##y = \sqrt{\ln({\cos(\sin (x)}))}## Homework EquationsThe Attempt at a Solution [/B] https://www.desmos.com/calculator I used a graphing calculator to find the intersection between ##y = e^{x^2}## and ##y = \cos(\sin(x))##. Which I get as ##(0,1)##. So the...

Homework Statement Initially there is a spherical charge distribution of with a radius ##R_0## and uniform charge density ##ρ_0##. Suppose the distribution expands spherically symmetrically such that its radius at time t is ##R_0 + V t##, where V is the velocity. Assuming the density remain...

https://www.sciencedaily.com/releases/2016/11/161130082804.htm Is there any other detection's to back this up?By studying the light emitted from an extraordinarily dense and strongly magnetized neutron star, astronomers may have found the first observational indications of a strange quantum...

Homework Statement This is kind of what the circuit looks like: Homework Equations KCL The Attempt at a Solution This my attempt at "normalizing" it: Solving Attempt: ##\frac{V_{in}-V_o}{R_1}+C_1\dot{V_{in}}=0## ##\frac{V_o-V_{in}}{R_1}+\frac{V_o}{R_3+R_2}=0## Are my equations correct?

Hi, I'm trying to work my way through some problems and am stuck on one for a symmetric infinite square well, of width 2a, so -a<x<+a. Since this is the symmetric case, the wavefunction should be a linear combination of the terms (a)-½ cos (nπx/2a) for odd n, (a)-½ sin (nπx/2a) for even n...

I'm sure that I am not the first one to notice this, but I found that for angles between 0 and 90 degrees, tan(90-10^n) approximately equals 5.7296*10^(-n+1). Is that purely a coincidence?

The so called weirdness of quantum theory seems to be widely publicised particularly in the non specialist popular literature. However many of the experts in this forum seem to be of the opinion that there are rational explanations to much of the weirdness. What I would like to know is the...

When I was 25 years old, I lived in a homeless shelter in a small town (population approximately 30,000). After I had been at the shelter about two weeks, I was eating dinner one day at the homeless shelter when this other homeless guy I had never seen before sat right across the table from me...

While I was studying with electric field about cylinder, I learned that for a very long cylinder, the electric field in the hollow of cylinder will be zero. http://physics.stackexchange.com/questions/156789/electric-field-of-hollow-cylinder However, I couldn't accept this intuitively, and...

Homework Statement [/B] Hi everyone, some school mates sugested id try this forum for help with this work i have :) - will try to keep it short We were trying to induce current in a coil and confirm the experimental results with math, but the math is way off and nobody is sure...

Homework Statement Homework Equations V=IR KCL/KVLThe Attempt at a Solution I have a similair problem to this one in my notes and I know how to solve this circuit, but I am confused on some parts of it. First, at V1 why can we say the voltage there is 0V? Is it because it is connected to...

So I am studying conditionals in proposition logic, and I have discovered that there are a variety of ways to phrase a conditional "if p, then q" in English. Some of the harder ones are... p is sufficient for q a necessary condition for p is q q unless ~p (where ~ is the not operator) p only...

I put the prefix as intermediate because I wasn't really sure how complicated of a question this is, I am currently a junior in high school... So basically if you were to have two spaceships with people the exact same age in them traveling at 99% the speed of light and they were traveling...

Anyone have any backup ideas/plans for me because it appears that my Air Force career goal isn't working out... as in they might not even bother to send me to MEPs because of an issue. Thanks!

Hi guys, I am currently doing HL IB Physics and i chose to do my Extended Essay on physics as well but i am having trouble to figure out my topic and what my question can be. I was thinking of something around the area of stability in structures or renewable energy. But i have no idea what...

Just refer to my profile picture to see what the issue is! :biggrin: Here's the problem: a ball of mass m is connected to a vertical pole with an inextensible, massless string of length r. The angle between the string and the pole is θ. The pole rotates around the z axis with a constant angular...

Hey, I'm new here, and I really need an explanation for this. It's been driving me up the walls! Also, it looks like this got posted in a different area then I tried to put it. Tried putting it in astrology thinking it might have something to do with a space phenomenon. I would delete this and...

I'm always finding weird things in the news and thought it might be fun if we all shared odd stories we came across. Please feel free to post odd, funny or unusual stories in this thread. Turns out that Zoobyshoe beat me in posting about this in another thread, so he will officially be known...

Hello there! I'm currently doing some mathematical modelling at my work, and I have arrived at an interesting kind of circular relationship integral - and now I'm wondering about what to do. The integral looks very innocent at first glance: $$ \theta_s = \int\limits_0^{t_1} \omega (t) dt$$ So...

Hello everyone, I have this weirdo potential for homework \begin{equation} U(x) = \frac{U_1}{ \left( 1+e^{x/a}\right)^2 } - \frac{U_2}{ \left( 1+e^{x/a}\right)} \end{equation} where U1,U2 and "a" are positive and I need to find the energies for the bound states and also the wave functions...

Homework Statement In the following circuit, the battery has emf ε = 12.7 V. The resistors are R1 = 2000 Ω . R2 = 3000 Ω, and R3 = 4000 Ω. What is the current through resistor R2 ? Homework Equations Kirchoff's Rules V=IR The Attempt at a Solution i0 (into A) - i2 (current into resistor 2) -...

I can't upload the notebook I guess, that would be a nice feature mods! (.nb extension) But here is my code , there seems to be a problem with integrating separately and then combining. $Assumptions = 0 < r < 1 && 0 < z < 1; FUNCTION = Expand[-(Pi*(-1 + r)*(-12*z + r^2*z + r*(-12 +...

In scientific daily. https://www.sciencedaily.com/releases/2016/04/160411130033.htm How can a cosmic strings align black holes , or any other process,

Just a standard introduction.

Hi friends , today we are just general talking with my boss. and he asked me a question . and that is, if we have equipment that is rated short circuit current is 40kA. for 1 sec. and if we must have to use that same equipment for 3 sec time. that how much short circuit current they can...

...so close to the Sun's position? Is this even possible? First two, taken around May 1st, 2015. Last one, taken in October, 2015

Dear Group, I have a 30_sec_data.txt with weird characters in it and data.txt with nice numeric in it, Any one have any ideal to help me convert data from weird to regular data using Matlab. Thank you, Best regard,

If I show you three face down cards (normal playing cards, so can be either a red or black suit), and tell you that no matter which two you pick, they would be different colors, I have no doubt you'll say I'm being weird (to put it mildly). Well, nature does pretty much the same thing. This is...

Inspired by stevendaryl's description of an EPR-like setting that doesn't refer to a particle concept, I want to discuss in this thread a generalized form of his setting that features a class of long-distance correlation experiments but abstracts from all distracting elements of reality and from...

Let's be fair, it's not true. Pure states are the ones that correspond to exact physical states. And it is not intuitive that exact physical states should transform continuously. Our belief about outcome can transform continuously but belief does not correspond to pure state.

Does quantum mechanics have to be weird? It sells much better to the general public if it is presented that way, and there is a long history of proceeding that way. But in fact it is an obstacle for everyone who wants to truly understand quantum mechanics, and to physics students who have to...

Hi folks , now I wonder today I was working on a cooling system , I drilled a small hole in a thin metal plate that was painted black, now as the drill goes through the metal it heats up so for a tiny moment there was this smell which i sometimes get when drilling wood for example the only...

In a rather bad science fiction movie, astronauts Susie (mass 60 kg) and Fred (mass 86 kg) are investigating an alien probe. All of a sudden, the probe starts to produce a weird defensive force field. Their space ship's board computer scans the field and produces the above plot of the potential...

Most original posts on PhysicsForums, in the more 'academic' categories (i.e. Math, Physics, etc), has the original poster asking a very specific question. It seems the vast majority of users just come here to get free tutoring or push past a roadblock or misconception in their learning. The...

Homework Statement find eigenvalues and eigenvectors for the following matrix |a 1 0| |1 a 1| |0 1 a| Homework EquationsThe Attempt at a Solution I'm trying to find eigenvalues, in doing so I've come to a dead end at 1 + (a^3 - lambda a^2 -2a^2 lambda + 2a lambda^2 + lambda^2 a - lambda^3 - a...

Hi, I've got a strange situation. I'm a teacher in a foreign country, and one of my students wrote stories about historical characters. But his stories are so good, that I'm not shure if he has written them himself... My suspision is, that he has taken some Englisch stories, and translated...

So, I foolishly bought a TI-89 Titanium on Ebay that was known to be in a locked up state. I've fixed locked up things before and figured I could here, too. Bad move. A thread here indicated that the hot car trick might fix it. I thought it had, but basically I think that was just due to...

I'm taking an engineering graphics class and I recently learned this rule which states: "When the digit next beyond the last place to be retained is 5, and there are no digits beyond this 5, or only zeros, increase by 1 the digit in the last place retained if it is odd, leave the digit...

Hi all, I'm a writer who is not really great at math so I need some help with establishing time rates between different "realms" in a world-setting I'm building for a story. The gist is this: Earth is there with it's normal 1 year = 1 year timeflow. There are two realms where time runs much...

Heya... I just stumbled upon this integral while doing ODEs... ∫x*(x-2)-2dx I used integration by parts u=x du/dx=1 dv/dx=(x-2)-2 v=-(x-2)-1 Thus ∫x*(x-2)-2dx=-x(x-2)-1-∫1*-(x-2)-1dx=-x*(x-2)-1+ln(x-2)+C Now... I don't see anything wrong with this... But every single online integration...