Thread Definition and 503 Threads

I am getting this error in Mathematica from the code below: Computed derivatives do not have dimensionality consistent with the initial conditions ClearAll["Global`*"] \[Mu] = 398600; s = NDSolve[{x1'[t] == x2[t], y1'[t] == y2[t], z1'[t] == z2[t], x2'[t] == -\[Mu]*x1[t]/(x1[t]^2 +...

Are you familiar with multiple languages? This is the thread to discuss what languages you like the best, what advantages/disadvantages they have over others, etc. I am familiar with C, Python, Ruby, Scratch, and JavaScript. That's all I can think of. IMHO: Python and Scratch definitely...

Hey Everyone, Just like in years past we should have a thread where we post what REU programs we are applying for and when we get accepted so we know when to expect decisions and stuff. Also feel free to discuss projects and ask questions so we can all help each other out. I thought we...

I always like to have some popular physics book by the bed for "easy" reading late at night. I'm almost finished with my current book, "The strangest man," a biography on Paul Dirac, and need to look for another. Any suggestions? I was thinking of Dancing Wu Li masters, but it seems kind of...

I don't think anyone really likes these threads, but I could use some assistance. Could anyone offer me some criticism on my statement of purpose below, for an REU? This one is really an amalgamation of a couple of ones that I wrote for specifically for different programs, which all more of less...

Hello all, I know it might sound harsh. I hesitated to disguise my question using another context but I hope some can analyse the exercice despite the emotion. I would understand also if you can't. If mods think i am out of line, please delete the exercice. Lets consider the following 3...

Hi Can someone please explain the answer to the following thread? I tried uncoupling the Hamiltonian but to no avail. https://www.physicsforums.com/showthread.php?t=602106 Thank you.

I am designing a mating male and female threaded interface, where the nut is much weaker than the male thread. I need to be able to calculate a few things: A. The maximum force (as preload) required to reach the yield point of the nut material. B. The torque required to achieve the above. The...

Hey guys - I've been looking to find an oxygen sensor that fits certain criteria. I've been looking through oxygen sensors on Google and I can't really figure out what kinds of inexpensive oxygen sensors are available that aren't meant to go inside car exhausts. I would really appreciate it if...

Homework Statement Two bodies with masses m1 and m2 are connected by a massless thread that supports a maximum force |Ft|max . On mass m1 the force F1 = -β t x and on mass m2 the force F2 = 3 β t x (t: time, β: constant) acts. The motion is frictionless. Homework Equations When does...

Homework Statement The world’s largest ball of string is about 2 meter in radius. To the nearest order of magnitude, i.e., the power of ten, determine what is the total length of the 4mm diameter string in the ball? Homework Equations The Attempt at a Solution I calculated...

Jameson, 1. I thought that because what I have integrated is essentially an area that it should be written as squared units (since the unit of measurement isn't otherwise stipulated) 2. thanks for the tip regarding mixed fractions; duly noted! "Using Tactic D-15 ..." You encapsulate my...

Hey you guys. I thought I sucked at math for ages. I remember in algebra class staying up till the wee hours of the morning and still not understanding that substitution concept. I'm still not sure if I should blame my teacher for not explaining the concept at all and generally being a dick...

"Urgent help with Forces, Components, Acceleration" - can someone delete that for me and this one too

Basic "Big-Bang" ?'s For First Thread I know this question is on the basic theory of the Big-Bang, but I'd like to propose simpler questions as my first thread starter (I literally just signed up to the site) in hopes to read the forums user replies and thus learning more about the different...

Sorry for this elementary question, but I'm just trying to avoid making a mistake that will lead to a bigger problem. I'm trying to change out a water valve in my garage. The little old lady that lived here before me pulled a little too far into the garage with her car... (I'm guessing). The...

This is the discussion thread for the Physicsforums bibliography. In this thread, you can suggest new books to be added to the bibliography and you can make comments about existing books. These posts will be transferred to the actual bibliography thread by a mentor. When suggesting a new book...

Hello guys I just wanted to say hi and introduce my self, my name is Albert I am currently doing my undergrad in Mechatronics engineering and this semester have a crazy electromagnetism professor and -_____- although I've been able to hold my own till know the test is coming and he gave us some...

Thought this would be a cool Idea - Everyone post your various study tips and strategies for dealing with upper level classes and graduate school I love keeping a detailed log of what I plan on doing during the day,I try to keep every hour filled in eve if it is non academic (Weight Lifting...

What's the best sticky thread about using LaTex on forum? I looked in my old posts and see I referred new users to https://www.physicsforums.com/showthread.php?t=546968, but that link doesn't work now.

Another "what are my chances" thread (astro grad). Some details about me and my undergrad institution: Senior physics undergrad at a Spanish institution recognized in the EU as the home of the most important observatories in the region, big collaborations with U of FL. Rigorous program that...

QUESTION: Say you have two spools of thread. Let's assume it's a sturdy, but mass-less thread. You unwrap one spool entirely and gather up the loose thread in your hand in such a way that it doesn't knot, and let it hang from a certain measured height. The other spool you hold from the same...

anyone read this article about latest relevation about dark matter? any thoughts? http://arstechnica.com/science/2012/07/dark-matter-is-the-thread-connecting-galaxy-clusters/

OK, I'm seriously struggling with this horsepower torque conflict, mostly because of all the god damn bias going around in these forums. It seems that the facts only go so far as to saying hp is a measure of power, and torque is a measure of turning force, then when people try to bring about...

Any anime fans out here? I was thinking of starting this thread to discuss some of the popular animes like Naruto, Bleach, Death Note, One Piece, Inuyasha, etc.

Hi all, I would like to know how to design a thread/screw to induce a specific stress on an object. What I have in numerical data is the stress itself that is required. The application is very similar to that of a threaded car jack. By turning the thread, it will lift up the load that was...

Yet another "should I study physics?", thread Hello folks, First, since this is my first post on the forums, a short introduction. I'm a 23 year old student (pharmacy - 5 years to go!) living in the Netherlands. As far as I can remember I have been fascinated by astronomy & physics...

I've always looked at the forums here, but never bothered to make an account or post, so this is my first post. Typically inquiries about finding instructor's solutions manuals are locked for advocating cheating, but most of the student solutions manuals I have are total garbage. I like to...

Can anyone offer a method or location of a method for determining the permissible axial load that can be applied to an internal thread? i.e. Take a nut and screw into it two bolts, one from either end so they meet in the middle of the nut, then apply a tension force across the two bolts. How...

What does the thread note 3/8'' - 24UNF 2B x 1-1/2'' mean? I know that the diameter of the thread is 3/8'', but what's the 1-1/2''? Is that the length of the thread?

Homework Statement Two small spheres, each with mass m = 5.0 g and charge q, are suspended from a point by threads of length L = 0.30 m. What is the charge on each sphere if the threads make an angle θ = 20° with the vertical? Homework Equations F=k|q1q2|/r2 The Attempt at a Solution I found...

Maximum Temp. that a 2" NPT (Pipe Thread) can withstand. Hello Forum I have a question related to Pipe threads. Does anybody know the maximum temp. a NPT Thread i.e,( National Pipe Thread) can withstand on a 2" piping without compromising its performance. It has 11-1/2 TPI (Threads Per inch)...

I'll start it off with a nice idea I found in another forum: http://www.energyfromthorium.com/forum/viewtopic.php?f=51&t=3433 Solar panels on the roof to keep battery banks for instrumentation and valves charged. Lovely and relatively inexpensive, might avoid the need for bigger battery...

Homework Statement 2. Consider a stationary circular spool of thread of radius R. Assume the end of the thread is initially located at (0; R). While keeping the thread taut, the thread is unwound in a clockwise direction. (a) Parameterize the path described by the end of the thread as r(t) =...

This YouTube describes the Rosetta mission Here is the print version: http://science.nasa.gov/science-news/science-at-nasa/2012/02feb_rosetta/ Rosetta is a European (ESA) mission with some Usa instruments on board. It carries a lander that will descend onto the comet surface, take pictures at...

May be another thread regarding "high level" education? Just stumped upon a news saying a little girl, who's only 14 and do nothing other than sitting in front of a comp all day, was hired (in my country there are legal holes) by a major outsourcing player as an intermediate software engineer...

Are you an artist, let us see your art, do not be a pansy,your art may look good to us.

Hi, I am trying to understand this Bell's Spaceship Paradox , which is basically asking when there is a thread connected between two spaceship (A,B) and an observer C observes a "constant" acceleration, then whether this thread will break or not by Lorentz Contraction. I think the problem...

This thread got me looking at Neutrinos for the very first time. They are the most recently discovered fundermental particles, the Tau Neutrino was first observed only 11 years ago in 2000. The neutrino was first postulated in 1930 by Wolfgang Pauli to preserve the conservation of energy...

Homework Statement Charge 1 (0.15 kg) in the following diagram is hanging from a light insulating thread, as shown in diagram (red is what I have added myself) Charge 2 is brought close and pulls charge 1 , deflecting the string away from the vertical axis by 40 degrees. The charges have the...

Another treadmill thread: am I more correct than a physics professor? I'm a freshman in college; I took AP Physics C: Mechanics last year in high school. Today my roommate and I got in an argument over whether or not it is easier to run on a treadmill than on flat ground. My friend argues that...

A newcomer named Mathbrain posed some questions/comments that need response, but posted in the balloon model sticky thread where discussion would likely be off-topic. I don't want to overload the balloon model thread with a possibly lengthy discussion so I'm starting a special thread for...

College Stress Help Alright I'm just going to get right to it. Right now I'm a freshman at BU studying physics, though I'm hoping to double major in math. And it has not been going very well. About a month ago I bombed my first set of midterms, but honestly I think I can attribute that to...

I realize this is not about photo's but video's. If mentors decide this should go in the GD forum then please move it. I thought it close enough. A start: http://www.youtube.com/watch?v=k0DWfgVxMX4&feature=mfu_in_order&list=UL"...

For anyone that doesn't know: silver is well known to have antibiotic and antifungal properties and many people claim it also has antiviral properties in vivo. Before the invention of beta lactam and other organic antibiotics, colloidal silver was the only antibiotic a doctor had at his...

Hello? Has somebody used or has experience about using Mathematica's code with multi threading for increasing it's capacity and efficiency or smth like this? My personal computer hasn't enough capacity to calculate all i need so now I'm looking for using Math on cluster. Thanks!

Everybody on the internet talks about inductors when they are in steady state. But nobody talks about inductor, when its in initial phase. Here is what I am talking about: We made a clear statement why voltage leads the current in inductor. And I understood that part quite well. But...

Does a left hand thread offer any advantages over a right hand thread?

So I was, in my pure innocense, googling for math word problems. Little did I know I'd only find word problems for kindergarten. Anyone got a good site for intermediate (17-21) word problems? Or just math problems in general? :D

Question : A balloon tied to a thread whose other end is fixed to the bottom of a beaker is held such that the string is horizontal. The path traced by the balloon if it is released is ? Answer : The path is along the arc of a circle Please explain why the path will be along the arc of a...