Welcome Definition and 170 Threads

Tonight's episode of Naked Science on the National Geographic Channel.

Hi all Can someone tell me what is meant by an "MC Vertex"? I'm coming across it in some analysis code. Thanks.

Simple yet challenging calc problem - please help! http://img252.imageshack.us/i/en8t.jpg/ a searchlight is located at point A 40 feet from a wall. The searchlight revolves counterclockwise at a rate of π/30 radians per second. At any point B on the wall, the strength of the light L, is...

Hi all I read in a book that coherent means when two waves are monochromatic and have a definite phase relationship. What is meant by a definite phase relationship?

Hello, I am new :) Hello, I'm Rohan I am 13 years of age and think it's time to start a physic's career much to my utter disgust since there's not much opportunity for me since I'm from Australia :rolleyes:. I have had a long thought and decided that i think physic's is a good career for me...

Welcome to the game of doors! Anchor: Alright then, you have three doors in front of you, A, B, C. Two of these three contain nothing, one contains the proof of the unified theory yet unknown to man :biggrin:. You can choose anyone door, which one do you choose? You: Uhmmm.. I think I'll go...

Hi everyone, I'm a new member. Just joined tonight, actually. I'm new to physics & cosmology. I'm here to learn as much as I can because it all feels natural to me. Hopefully some of you can better help me understand the basics and help me learn all I need to know. :blushing:

welcome all I'd like to know if there is a way to calculate how manny photons are in this universe. We can calculate the mass of the universe so is there a way to claculate the number of photons? I also would like to clear some things i don't understand. I read that if people build a ship...

So the deal was a new kitty after the move from the 14th floor back to ground level. I guess my daughter found her, It's the one in the center here having obviously the most interest in the environment at three weeks of age, unlike her black brothers to the right. Her name may become Pebbles...

Moon --> Earth (Gravitational Pull... help please any comment welcome! Homework Statement At what distance (AU) does a spacecraft leaving the gravity of the Earth traveling toward the moon balance the gravity of the moon? I.E. What distance in (AU) will the object begin being affected by...

Hello, I am new! Hi! I am new to PF and I am Considerably new to physics. I have been interested in physics since i was in year 7 (a year ago) so that makes me 13 years old. I am not learning physics at school, but i am very keen on physics and astronomy. It is kinda easy for me to introduce my...

Please welcome another imaginary friend! This time, he's a renowned Prehistoric Archaelogist, also considered America's most hated Archaeologist because he stands up against unfounded personal theories (fits right in here). He was compared (in a 1999 article in Scientific American) to Brad...

My father has signed up! His username is Greg'sDad... how creative! :rolleyes: :biggrin: His first topic is here, please welcome him and help him out. https://www.physicsforums.com/showthread.php?t=238236

Homework Statement Does anyone understand the basic theory behind NMR experiments such as the one shown here http://www.ifw-dresden.de/institutes/imw/sections/22/laboratory-for-pulsed-high-magnetic-fields/nmr/nmr_exp.gif. If so I have questions.Homework Equations The Attempt at a Solution

hello everybody do u know how to find the number of dative bondings in a molecule without drawing lewis structure?please help

Hi everyone I am a new member of this forum and I wonder how can I use those Latex codes for mathematical slymbol displays? I try typing those codes but it came out just the way I type them, do i need to install something before I can use those codes?

Hi everyone this is a fantastic forum ,I have browsed through the threads and found it fantastic to such a community for engineers to share knowledge ,experience and advice. It will boost the mutual interests of members ,so consequently I registered today and I would like you to...

You're back!

The problem is to give a projectile an initial velocity such that it lands a certain height and distance away (2D system, only x and y dimensions). The forces to account for are gravity and air drag. The knowns are x is target horizontal distance to travel y is target height to travel g...

Greetings to all Forumites ! I am new to this forum and this is my first post. If the subject of my post does not concur with this section, pls excuse me and redirect me to the correct section. Thanks. My interest is in ballistics, particularly internal. Most of my questions and discussions...

Hi! I believe a shipyard working on new ships, with all its electrical arc welding and stuff, makes for a lot of "stray" currents in the sea. Do you guys have any plausible idea to re-create such scenario in the lab? A small-scale model perhaps? Thanks a lot.

:smile: Hi, I'm new here (duh!). I just wanted to introduce myself. I am a first year BSc student hoping to major in maths. Seems like a fantastic site!

Hey, I haven't worked on an old computer in ages and I'm not sure if anything was around before PATA... I'm asking this because I see no PATA ports. All the ports with the right "size" have one extra pin. Do I just have bad cables?

This is just to welcome my son, Cale Micheal Baillie, into the world, he was born at 12:16 pm (MST) today, weighing 6 lbs, 13 ounces. I will post pictures soon.

I'm not much for country but I love them for what they did - they stood up for what's right when it counted and came out publically against Bush. Welcome back Dixie Chicks! http://www.pbs.org/klru/austin/artists/DixieChicks.html The crowd cheered when they sang "Not Ready to Make Nice"...

tough induction! hey ! I'm new here... :redface: I'm looking for a really tough induction! I will appreaciate who will write here some inductions.. thanks... * I JUST LOVVVVVE THOSE SMILIES ! :-p

Welcome to Zenmaster99! Since he hasn't introduced himself yet, I want to welcome a friend of mine to PF. Zenmaster99 is yet another crazy physicist (crazy enough to associate with me :smile:). Feel free to whack him with as many welcome fish as you want. :biggrin:

Hello everyone, For my programming class we have to find somthing we want to code and do it, and it must be at least 1,000 lines of code. This is an indepedant project we have to work on through out the semester. This is an internmediate programming course so it doesn't have to be that...

Hey! I finally got something I wanted to get done. You guys are the first to see the website. I won't be publishing the link to the website for another 2 weeks. This is my comic strip that I write at my university. I write one issue every week. The website contains an extra one at that...

Just in time for Christmas, a lizard is expecting a virgin birth! Now THAT is what *I* would call an immaculate conception! http://www.cnn.com/2006/WORLD/europe/12/20/uk.komodo.reut/index.html Zz.

Please don't tell me that I'm one of a hand full girls here??! lol Alright, here I am.. Just wanted to scream out loud: [SIZE="6"]HELLOO cya

HELLO EVERYBODY I AM A NEW MEMBER .WELCOME ME BY HELPING ME IN DIFFERENCIATING BETWEEN SCREWS AND BOLTS THANKS AND REGARDS NAVEED1114@HOTMAIL.COM

Dear colleagues, In order to celebrate the first year of Christine's Background Independence, I'm inviting anyone interested to send their contributions. See the blog page for instructions: http://christinedantas.blogspot.com" Thank you very much! :biggrin: Christine

When you joined PF, which did you choose for your welcome snack? I wonder if we should add another option. Should we start handing out those leftover triffles that Wolly is trying to unload?

Any enviromentalists do not look . So do you want a fast vehicle? i am trying to get a classic 1960 motorbike to go faster, i know it will never reach current motorbike standards, but it is the challenge, with some nostalgia ,that drives me, any engine gurus out there? if so your advice...

Hello, I'm brand new here; needless to say, I think it's great what this community is doing. Now to my question: my class is just finishing up geometry, which means we're starting to enter into beginning trig. Here's the problem: 1-Sinx/1+Sinx = (Secx-Tanx)^2 So far, I've been able...

Guess who! Hey hey hey hey hey! I'm back and badder than ever... i think. Been a busy old time but now I have no job, I have nothing better to do than try remember my password to get back on here! It must be some kind of sense I have, being tribdog's birthday and all. I'm the best present...

I am back, i can see loads of things have changed, Evo looks different from how i remember her, " sorry to read about Evo childs pnumonia". So what has been occurring in my abscense? I have a few stories to tell, but they can wait unitil later when i have all your news. What has Evo, MIH...

Hello all, Its my first thread here! I'll start things off with a (simple?) question. Suppose a block is suspended on a surface of water. It comprises potential energy quite obviously. As the block desends down the water level, it loses PE. According to the rules of conservation of energy...

Hello chaps, Just checking in again. Tesco (aka big idiots) keep postponing activation of my broadband. Not a good enough excuse for not being a regular in here, I know, but I'm doing my best and hope to be with you again permanently shortly! Anyway, things are still fun. I've been given...

I am trying to learn more about air coupling. That is the coupling between 2 shafts I am having a hard time finding any information on the subject matter does anyone know how these systems work and have any diagrams? thanks

Welcome Back Franznietzsche! Thank god you returned, these menial peasants were beginning to bore me with their incessant chatter and meaningless lives.

http://www.piratesstore.com/images/store/flag_images/flags-wh-band-155.gif Arg Mateys! I am yer Captain Pillowhead! This is the Pf pirate ship, the SS Galenog! all ye who board best be ready fer fantastic adventures and treasures beyond yer wildest dreams. All you scallywags prepare to set...

Hello All I am having problems Verifying this identity (COS A) / (1-SIN A) = SEC A + TAN A I can get the RHS = (1 + SIN A)/COS A But this does not equal the LHS Any advice is welcome. THanks

i was thinking can anyone findv the area of a straight line and also can anyone determine the area of a point or dot as the case maybe ,any suggestions wiil be appreciated

You have been sorely missed. What PF abstinence symptoms have you experienced?

Hello! We've begun a new project in our Physics class, and the objective is to walk on eggs with shoes designed by each group. My problem is designing the shoes. I have learned that we need to increase the surface area of the shoes to reduce the pressure, but I don't know of any ideas on how to...

Hi, well I'm new here.. and I wanted to congradulated you guys for making this awsome community... I've been sick all week & I've stumbled upon this forum... I read a lot of stuff here & learned way more then if I went to school... anyways that's about it, I should be around here now hoping to...

Happy New Year - reply to Lubos HAPPY 2005 EVERYBODY Let us welcome the International Year of Physics! There is a poster on the wall in the corridor here, saying "Help make 2005 another miraculous year". Well, I don't know that I can do much - but one can try. I've posted here...

Hi everyone, as you can see I'm new to this place and this is my first visit. Although I haven't seen much yet, I'm already fascinated with this place. To tell you a bit more about me I'm 14 years old probably the youngest or one of the youngest members here. Despite my age I believe I can still...