Discussion Definition and 276 Threads

A person is inside a car. This person is not using the seat belt. The car crashes with a solid wall and decelerates quickly. The person, due to inertia, keeps moving until stopped by the wind shield. I want to analyze the movement of this person after the crash, but I am troubled...

In addition to the Global Guidelines, these rules also apply to posts in the lounge. Overly Speculative Posts It is against our Posting Guidelines to discuss new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current...

Is there a thread for must-read books where people share some of the best books they have read? If not, can you start one? I like reading and I'm sure I'll get some great book recommendations here.

I would like to explore possibilities of production of really cheap hydrogen by finding a substitute for scrap aluminum in the current hydrogen on-demand known reaction: 2Al + 6H2O -> 2Al(OH)3 + 3H2 (catalyzed by specially treated carbon, carried out at 85 °C.) The above reaction is scalable...

This is discussed in Weinberg's Quantum Theory of Fields, in the chapter on Relativistic Quantum Mechanics. The point I am somewhat confused about occurs on page 63 - 64, if you have the book. He operates on a single particle state with the unitary homogeneous lorentz transformation...

FREE WILL, DETERMINISM, QUANTUM THEORY AND STATISTICAL FLUCTUATIONS: A PHYSICIST'S TAKE Any attempt to link this discussion to moral, ethical or legal issues, as is often been done, is pure nonsense. The fact that it is possible to say that a criminal has been driven to kill because of the...

Hello, can someone tell me a discussion for one of my physics labs? Aim: To determine the centre of gravity of an irregular shaped object which is a lamina. Apparatus: Cardboard, Pendulum bob, string, retort stand, Pin, Cork, Pencil. I have already determined the results and all i need is...

Homework Statement When you drop an object from a certain height, it takes time T to reach the ground with no air resistance. If you dropped it from 3 times that height, how long (in terms of T) would it take to reach to the ground? Homework Equations displacement=V0t+.5g(t)2 The...

I know little about this topic, yet it interests me beyond imagining. What can you guys tell me about it? Anything at all

Quick question. I'm currently(started today) working on research centered Faraday's Law with an application in automobiles, and I'm just looking for some good articles/academic journals/research papers on Faraday's law to get a better understanding of it. I gained a brief understanding of the...

From my understanding the image we see of a star isn't a reflection of how that star is now. The image we are seeing of those stars is millions, or billions of years old because it's taken that long for the light from the star to reach us. Is this correct? But, let's say we could travel to...

I just posted a question to ask for help on the Calculus & Analysis section to determine how fast planets go into stars. I should give a little background, in addition to pointing you to my latest two short papers: http://arxiv.org/abs/1301.4229 and http://arxiv.org/abs/1211.1984 I have...

I'm posting this here because I did not get much help from the Chemistry section. Please read further. Anyone familiar with the Boehm titration procedure and calculations? I've done the titrations based on what I was able to gather from literature and the calculations but the results don't...

Hello all, I've been encourage by my professor to participate in an open discussion regarding the article I've attached to this post. See below for link! The article is quite dated as it is from IEEE SPECTRUM June 1985, but it is nonetheless still useful. As a brief summary of the...

In another thread, Dalespam posted this paper: http://arxiv.org/abs/gr-qc/0311038 The paper is, overall, very nice and introduces a very convenient unification of all coordinate systems for the spherically symmetric vacuum GR solution that manifest the static character ( of the exterior...

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 I took a general physics course 2 years ago, and now I am trying to refresh a bit on my knowledge of physics so I started solving discussion questions+problems in University physics by young My problem is I can't verify my answers nor can I look for the correct answer if I don't know...

Edit: I think I may have posted this in the wrong section, sorry about that. Note that this isn't a homework problem though, I"m not enrolled in this class, I was just reading over some of this stuff and trying some problems since I"m majoring in physics. I have a textbook "discussion" problem...

Specifically: 1. If there are two (horseshoe) magnets that are facing each (unlike poles facing ea) other and an iron ring is placed in between them. Why are there no magnetic fields inside the iron ring? - As far as my understanding goes. I believe that there's no magnetic field inside the...

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.

I have attached a discussion by R.Feynman where he derives the formula for gravitational potential energy using pure reasoning. I don't quite follow the reasoning and I have read the discussion many times yet can't get a grasp of things he says. With the discussion I have my doubts in red...

QUESTION: WHAT DO YOU THINK THE ETHICAL ISSUES WOULD BE IN THIS SCENARIO QUESTION: WHAT WOULD BE THE IMPLICATIONS ON THE CODE OF ETHICS CASE: Laura’s Dilemma Laura Jenkins is a qualified environmental engineer who graduated from the University of Stoneybrook two years ago. Laura works...

Homework Statement Hi, I did a lab for a high school physics class where we measured the mass of an electron using a solenoid and our working equation was this: m = qB2R2/2V I was able to do the lab and get good results, but I have discussion questions I don't know how to answer. I...

Is anyone here into modular synths? Does anyone here own a modular synth or has heard of them before?

Interesting discussion on the "crisis in higher education" Hi everyone. I have found the following interesting post regarding the "crisis" in higher education (a topic brought up in numerous posts here on Physics Forums) from the blog of Aaron Clauset, a physicist turned computer scientist, and...

Anyone heard about this yet? Work Act: I'm curious what peoples thoughts on this are.

I'm looking for opinions on a little disagreement my fiancee and I had this weekend (Easter). This wasn't a big deal, just something we talked about for a min or two then let it go ... I'm not even planning on bringing up the comments made here to her, I'm just curious. So I have a pretty...

America made a lot of enemies so they need a powerful military -or- America has a powerful military so they made a lot of enemies?

Mod node: This thread was split from this other thread, 590162. [/color]Hey vkash. This is a good one. See, instantaneous angular displacement is a vector. Average angular displacement is not a vector.What does this information tell you about instantaneous angular velocity and...

So here's a question for you, if on a line we chose one point, then what is the fraction of this point compared to the line? I think we all agree that between two points there are infinite amount of other points, correct? So what fraction of a line is one point among infinite others? Isn't it...

Hi all, I'm looking for books or papers that give a pedagogically clear and reasonably up-to-date discussion of various experimental techniques in condensed matter physics. For example, ARPES, STM, NMR, muSR, ... As I suspect may be true for many theorists, I learned what I know of...

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...

I recently saw on an episode of NOVA yesterday, a machine made to detect muons ... I haven't heard of them before this. What it was used for was too see inside a volcano, Successful ? ... Yes. How did it work I have no idea. What exactly is this and does anyone else know of any other projects...

Note: This discussion question is from my University Textbook, as it so happens you can only get the solutions to half of the odd numbered exercise questions... Disclaimer: I have been trying to wrap my head around this answer for a good 5 hours now, so it's not like I'm coming here to be...

After many years of mental health treatment, untreated ADD has come up as a possibility. I have been prescribed accordingly, etc. so I'm not asking for medical advice. Anyway, For the past week I've been reading on the internet about ADD to educate myself about the disorder, but I've mostly...

Post any thoughts or ideas here.

Lets say two particles are entangled with each other. One particle is put in a spaceship, while the other remains on Earth. The spaceship then increases its speed till it is nearly at the speed of light. How does the time dilation effect influence the properties of entanglement? How does...

Hello, I was reading into self-organizing systems and I decided to post on a few curiosities that i stumbled over because members here know more about this topic than I do. So if any of you will, give me some insights. [I am an undergraduate math student] I know a lot of findings within...

Hello, I was reading into self-organizing systems and I decided to post on a curiosity that i stumbled over because members here know more about this topic than I do. So if any of you will, give me some insights. [I am an undergraduate math student] I read that studies suggest that through...

I'm doing a very short presentation on a laser. I want to discuss the most important concepts of a laser (in less than ten minutes). What should I include? I was thinking about stimulated emission and amplification. (But I'm not sure I really grasp these concepts) For instance, does...

PForums, I am a writer working on a novel and as part of my job is to research the science behind any idea, I have to make sure is it plausible in real life. I did some research about three years ago for the novel I am writing and got the opinion from scientist and medical experts in regard...

Hi all, May i know anyone here have been involve in aircraft propeller balancing before? i was requested to do test on aircraft propeller static & dynamic balancing using Bruel & Kjaer vibration equipment. May i know anyone have any experience with it and mind to share with me? thanks

Homework Statement Hang a heavy spring from it's top. Let it hanging down naturally. The total mass of the spring is M. The spring constant of the spring is k. Asking it's extension. 2. Homework Equations Describing the potential energies( spring force energy or gravity) with...

A little philosophical electric discussion... So, am I understanding this correctly? The movement of electrons is the fundamental interaction of all that we know...right? It's the driving force behind chemical reactions of all kinds and those are at the root of, well everything...right...

Say I launch an object (a cart) up a frictionless inclined plane at an angle of 'theta' to the horizontal. Question: What would be the acceleration of the cart right after it is launched? My guess at the answer: 9.81*cos(theta) since the cart is launched at an angle. BUT I'm not sure...

Fe is my favorite element. I love her less-than-absolute, yet still high, opacity to thermal energy as well as her status as an enormously capacious reservoir for the same. (As in: "I don't want it, but I'll hold on to all I can get!"; Fe is clearly the element with ATTITUDE!) I love that...

Does anyone know a physics forum where theory discussion is allowed? My first post was deleted by a mod for trying to discuss ideas.

I'm looking for a book that approaches it from preferably a physics slant (in terms of invariance, conserved quantities, and the like) but every mechanics textbook I've looked at gives a poor description. They're heavy on the math but they lack explanation or discussion of the results.

Hi guys I'm new here. I've got a lot of spare time at the moment so i was thinking of delving into physics a bit more. There is this guy called Cristoph Schiller who's written a 6 volume work called Motion Mountain. I find it a delight to read because i mostly understand what he's saying, but...

This is more an applied physics question, but I was wondering what the space shuttle would look like if we designed it today. I've got some project goals in mind: -Minimize design and construction costs ----design should use existing and developed technologies to minimize cost ----design should...