Thread Definition and 548 Threads

So after posting the blur contest, I did some experimenting with trees in the wind and the sun. Camera on tripod, telelens 70-300, all controls manual, exposure 1/4 sec while zooming in Same exposure but letting the wind do the blurring work Same exposure while making circles...

why is it that you post on 'pf random thoughts' once and get notifications for eternity but have to keep on checking 'best guitarist ever' for new posts?

Anyone listen to this show? It's about the most interesting show on imo. For the people who don't know what coasttocoast is about it's a radio show that talks about lots of "wierd" topics. Anyhow tonights episode... http://www.coasttocoastam.com/ includes an interview with Buzz Aldrin so...

I've seen a few people posting their failures and successes in various threads, so I figured it'd be a good idea to have one combined thread where you post how you did this semester. What classes did you take? How did you do? Did you get any research done? What other trials and tribulations did...

I thought it might be fun to have a thread to show our fossils. Everyone dig up your fossil picks. I found this rock this morning. The fossils range from 400-500 million years old. I'll post more as I dig my pictures out. I'm posting the kansas fossil page for what's on this rock (from...

Another "Late in Life Physics" thread I should really say "Really really late-in-life" I'm 56. About 20 years ago, I flushed myself out of grad school (physics) largely over just being fed-up. Lately I've been reading again because of the huge number of very good books immediately...

Is there any point at all in learning Latin?? I know this is the 21st century, but there must be some little use for it right? For Mathematician/Physicists.

I was shooting some macro pix in the park today. Actually I was targetting this lichen in that pic: and this one: But it's more about the new life: Feel free to share your spring pictures.

Find an interesting article about a new technology, new design, and whatever else is related to things that fly? Post her here!

At 733,000+ views, it looks like The Caption Competition thread in the Fun and Games Forum has a chance. Do we have any other contenders?

So, the time has come that grad school decisions are coming in. Anybody received any acceptances yet? I have applied to 8 schools for a master's in math and have gotten accepted to two - Miami University of Ohio and Bowling Green State University.

I drew a picture of Leonardo Dicaprio. Here's one I drew of Jackie Chan.

Whaaat? Nobody has started a first post thread? Jees. Fine, I'll be the radical bad boy and make it. Hi! I'm Joe. Nice to meet you all. I'm a Physics Major in Western Massachusetts (no e, lol) and currently attempting to find a new college because the one I'm at is just abysmal. I've...

Hi, I was just wondering why paragraphs containing inline LaTeX have extra line breaks or line spaces after the line containing the TeX image? I was also wondering why I don't always see new posts in threads I've subscribed to in "My PF" unless if I click on the link to see all subscribed...

After participating in a more algebra-oriented REU last summer, I would love to try working in some area of geometry of topology this year. Unfortunately this seems to be a pretty rare field for REU topics. Here are the programs I have found so far that have geometry or topology projects...

Hi, I'm learning Bipolar Junction Transistor and need help to confusion which arise so I will keep posting questions which I don't understand to this thread. Thank you in advance. So my questions start: When using hybrid pi model and t model, we determine the dc operating point first. In one...

Stimulus spending (split from "cap& trade" thread) Don't worry, Obama can spend $10,000,000,000 per year for 10 years with one hand tied to the tele-prompter.

I want to tap a NPT (NPT-3/4) thread hole on a plate. And I found some related standards, these standards told me the detailed dimensions of the thread. My question is how to machine the NPT thread with a tap? How to control the parameter mentioned in the standards? thanks in advance!

I can't decide what I should make for supper. As this is a semi-regular occurrence, I figured I would pawn off the decision on you guys ask you guys for advice. I can't be the only one who has trouble deciding what to make all the time. Just post whatever you're making for supper each day...

Homework Statement Hello, the question itself is pretty abstract. When pulling a thread roll, there is an critical angle, where the thread does not start to unwind itself. Instead, the thread roll itself starts to move. Derive an formula for determining that critical angle. Homework...

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Afternoon everyone, I am slightly confused... Basically, i will be purchasing a force transducer from a company called HBM. Now, on their data sheet it shows that there are two tapped holes either end of the transducer, designated by G and G1. I am using a 125kN transducer, and for G...

I've been browsing the forum, but I haven't found a way to solve this thing, which has been frustrating me for quite a while, I'm trying to develop a simulation of cue formation and propagation on cars on a single lane road, and of course, I have to compute the acceleration of vehicles obeying a...

Probably a stupid question but... I have a device with a bolt that is designated #6-32 UNC. I need to drill a hole in a surface to for this bolt to fit into. How big should this hole be? If the material I am going to be threading the bolt into is plexiglass do I need to thread the hole I...

Yet another "Which Career/Major?" thread. Hi, recently I've realized that I really need to start exploring majors/careers soon. I figure everyone here would be knowledgeable in that. I'm not sure what kind of information is needed, but here's what I think is related. If you're too lazy too...

https://www.physicsforums.com/showthread.php?t=335357

Where was my MS in CS or MS in IS thread moved? Can it be accessed from the main forums page? If I can't find it, how can anyone else. Thanks, cswave

hello everyone, this is my first post. Right now I am trying to figure out which equations to use to solve the following. I will have a block that will a threaded rod through it. This block will be next to another larger block. In between these blocks are going to be metal samples. Now...

"L di/dt" vs. "i dL/dt" I have heard many times that the positive "inductive" part of a circuit's reactive power is equal to "L i di/dt". I also know that "L di/dt" is just one of two terms that is derived from applying derivative of "L i" with respect to time. The other term is "i dL/dt"...

Yet another "which math course to take?" thread Dear PF members, First, I would like to apologize in advance for asking this type of question repeatedly. I just haven't made my mind yet, and I just think getting another advice from PF members might be helpful. So, I'm going to be a...

If we can shoot a photon outward, at velocity c, why is it that the body that shot it outward is not traveling away from the photon with velocity c?

Please delete << berkeman merged two threads >>

I am trying to do some preliminary calculations for a basic lifting device but some of my numbers seem to be out-of-wack. Could some kind soul take a look if you have a minute spare? Motor Data (max efficiency) RPM: 8311 = 870 radians/sec Torque: 9.213N-cm = 0.09213N-m Output Power = 870...

It's one of my passions. There were a few earlier threads in which it was discussed, but I decided to start a new thread devoted to mountain climbing and trekking. The 2009 Climbing Season in the N. Hemisphere is in full swing. http://www.k2climb.net/news.php?id=18533...

i've been away more than 5 yrs and can't find the thread that used to tell you how to code latex. you could practise there too without burdening others with your errors. where is that thread? or something similar? in friendship, prad

A while ago I saw a rainbow while I was driving. The end of the rainbow lay right on the hood of my car. When I came to a stop, I popped the hood to see if there was a pot of gold in there. Of course, by then the rainbow was gone and so was the gold. I said I would post about it, but forgot...

I thought it might be fun to have a thread to make your head explode! By means of posting some of your favorite mind-bending paradoxes. I just heard a new one (for me) today that I thought was pretty good, thought I'd share! What if Pinocchio said "My nose will grow"?

Hi, I am trying to calculate the capacitance of a non-parallel plate capacitor and there has been few discussions on this research in this forum. Some of the people have pointed to this material by Fred Erickson, The material link is not valid anymore. I was wondering if anybody has...

Homework Statement A 2.60 g spider is dangling at the end of a silk thread. You can make the spider bounce up and down on the thread by tapping lightly on his feet with a pencil. You soon discover that you can give the spider the largest amplitude on his little bungee cord if you tap exactly...

Another black hole thread... So what exactly is the difference between a rotating black hole and an non rotating BH? I am not exactly sure what the difference is so i decided to ask the enlightened ones. Thanks all!

This thread is about TED. Clip 1: smart people art. [url]7zT7iKmfrCU[/youtube]

This thread is intended to give high school students the necessary information to cope with university level mathematics. I find the “who wants to be a mathematician” thread too convoluted to be of use when looking for books, and that it serves college students more than k-12. Nonetheless, it...

Hello, [aside] So I've seen a lot of medical physics related posts on this forum recently, as well as some good answers to questions (thanks go out in particular to Choppy!) and would like to get out-of-the-way my support for a medical physics subforum. Anyway, on to the point. [\aside]...

I just watched a cooking show on tv which showed how they always boil lobsters till death. We people have done some sadistic things in the past. Being cooked to death was one of them. How long could one survive?? I'm thinking you'd die pretty fast because water is such a fast conductor...

There is no reason single people can't have a good time on Valentine's day! We just need our own holiday, "Anti-Valentine's Day": http://www.msnbc.msn.com/id/17011635/ Happy Anti-Valentines, single PF'ers!

The "Get Well Christina" thread lisab already poured hot chicken soup on you so I thought I'd start a "get well" thread. Get better!

I have this strange feeling, the solution is almost ready, I believe we are already entering the age of Free Energy. But no, it won't happen overnight. If I may ask, what source of energy exists anywhere in the world? Constant and is always available, completely safe and doesn't emit harmful...

I have a reciprocating pump running 350 RPM, 2.25" stroke. Piston is double acting (ie: force in both directions). Load is ~30,000 pounds. There's a very small clearance in the coupling between piston and drive train, and this coupling goes through the same motions as the piston (it is...

Amidst the current financial crisis, and possibly heading towards a recession (if not already in one), it begs the question as to how did we get into this mess. Then, when one starts looking into the system, something seems a bit confusing... if a recession means that the majority of ppl does...