timo

Makes me wonder in which respect posting on an Internet forum can be considered "effective" at all.

Someone should inform the real numbers about this floating point representation standard so that they can adapt to it.

I see three recommendation, not two. I assume you mean 1) Thermodynamics and Electrodynamics, and 2) Philosophy of physics? I am certainly against creating (2) for several reasons (unless someone finally implements the feature to put sub-forums on the ignore list, in which case I am much in favor of it). But what what interests me: Why thermo&Edyn as a common forum (assuming I understood the proposal correctly)?

If you are willing to stretch the term "atom" a bit (and in particular extend it to constructs that blow up within less than a second), then Muonium may qualify as an example of a lighter hydrogen atom. Of course, its properties are not exactly that of a hydrogen, but that you already put into your question (different mass).

At the moment I am most fascinated by how the sum of random numbers/effects can be predictable. Admittedly, the extent to what this qualifies as physics is debatable (it definitely plays a huge role in physics, but by itself it may be argued to be math). In the past, I remember that I found the property of linearity quite amazing. Again, that is arguably not that much physical by itself. But it but pops up all the time in physics (with "superposition" probably being the most widely known instance).

I would imagine history to have the main effect and education level, and social security system to play a minor role at best. For example, Malta (the tiny 95% rock in the ocean you mentioned that technically counts as a country) has been ruled by a knight order of the roman church from mid-16th century till the French revolution (~1800). Italy, another country with a high value, has been the center of the roman catholic church, the largest religion in the world, for more than a thousand years. The countries on the low end of the spectrum are (with the exception of France) countries that did not play a huge rule during the super-religious middle ages, where church not only completely dominated everyday life but actually ruled parts of Europe. I'd expect that the low religiousness of the French can be traced back to their revolution (for the non-European readers: in Europe, the French revolution is usually considered as the turning point from a god-blessed monarch to a concept of citizenship and participation of the people). A difference between Europe and the US may be that the more-religious countries in Europe are catholic, whereas most of people in the US are some flavor of protestant (there also are protestants in Europe, but they tend to be in the less-religious countries, mostly). I'll skip the tendentious discussion of talking about the implications of this difference. But I know a lot of people believing that there are quite a lot of religious zealots in the US, whereas I've never heard the same being said about Portugal or Italy (except for certain parts of the institution called "roman catholic church", that is).

I remember having been called to an emergency where upon arrival the patient was alive, but had had received CPR by a neighbor who was present at the time he dropped dead (*). That fits rather well to what IA said above, namely that successful reanimation by CPR alone can happen, albeit extremely rarely. For the whole thing about survival rates you also have to keep in mind the state of the patient. In some cases an otherwise healthy person just drops dead (who has very good chances of successful reanimation), in some cases no one really wants the patient to survive (and in some very lucky sub-cases you even have a written document of the patient declaring he doesn't want to, either), and performing CPR on a person that died from blood loss is technically possible (and required by law), but rather pointless in the first place. (*) Naturally, I can only give the story the neighbor told us. The patient may in principle simply not have been dead, but merely appeared so to the neighbor. @Hypercube: I felt that you answer was already answered, but I can of course restate the points already mentioned: - CPR alone can not save a person's life as well as CPR + defibrilation + proper artificial ventilation + Adrenaline + Atropine. At least not in all cases. That's why you add the "pluses" in professional reanimation in the first place. - It can happen that you perform CPR to a person that you assume being dead, and some time later find that the patient breathes, again. - I've never seen a person to "suddenly jerk up with a loud gasp as their heart and lungs start working on their own again". Also not after defibrilation. It doesn't make that much sense to me, anyways: if the body is severely weakened, I would expect body function to set in slowly and weakly, not suddenly and strong. That is, of course, also just my personal impression and not the result of a scientific survey.

So astrophysicists performed a measurement fully compatible with mainstream physics that constrains the parameters of some not-further specified set of other models such that the extra parameters cannot have arbitrary values, anymore - unless the model is expanded by even more free parameters, of course . My first thought is: Boring. (but hey, that's just my personal first impression, and possibly due to not being familiar with the motivation for "5th force"-models in the first place)

The intellectual lemming would point to Wikipedia now: http://en.wikipedia.org/wiki/Cardiopulmonary_resuscitation#Effectiveness

If I remember correctly from reading a statistic about the topic several years ago (when I worked in the field), it raises average survival rates significantly, namely from practically zero to a two-digit percentage (which I think goes up to ~50% in case of immediate CPR performed by professionals).

I could throw around buzzwords like "strong force", but on this level, the standard explanation (that should suffice for now) is that the neutrons act as a glue for the protons. In fact, a nucleus with 2+ protons from which a sufficient amount of neutrons are removed does become unstable because of the protons repelling each other.

I fully agree that your new modified post #3 is more appropriate than the original I responded to. Considering the intellectual honesty that you just demonstrated by deleting your statement but quoting my now-out-of-context reply to it, it's EOD for me at this point.

It's the backup system when you run out of photon torpedoes, right?

If by "induction" you mean that the surrounding material reacts to the presence of a charge and becomes electrically polarized, you are correct. This should indeed also alter the net force between two charged objects in such a medium. However, I have my doubts that the relation [math]F=k q_1q_2/r^2[/math] holds true in water at all. Are you sure it's not a [math]k®[/math] (or that the "1/80 the value in vacuum" refers to a given distance) in the source where you have that from?

Well, force and acceleration are vectors, I merely didn't write down the arrows over the letters. I could also write it as [math] \vec F = m\vec a \Rightarrow \vec a = \vec F / m[/math]. Like I said, I'd rather expect you to have problem finding the force, i.e. the force vector. It's not that hard, but if you get stuck, you're welcome to ask for more help here. For question about forces and working with vectors there should be plenty of people in this forum that can and will gladly help you.

You'd get the acceleration from F=ma => a=F/m. But I have the feeling your problem rather is to find the gravitational force.

I'm not sure what you are trying to say here. Relativistic corrections being caused by relativity seems a rather trivial statement to me. Am I wrong in saying that you essentially think in terms of non-relativistic physics and merely add a few correction terms at appropriate places in the calculation? Let me try to reformulate my statement: When it comes to the timing of GPS signals, you (or at least the people working in the field) have an idea what the outcome would be if you performed a non-relativistic calculation. In e.g. particle physics, I wouldn't even really know how to perform a non-relativistic calculation in the first place, less could predict the differences to the relativistic calculations. Hence, there are probably applications(*) that are even more dependent on relativity than GPS (which I guess would merely become more inaccurate - possibly to the point that you'd rather navigate via stars) , but are less obvious because of that. (*) particle physics admittedly is not exactly renowned for its wide range of applications - that's why I did chose the related nuclear physics in my previous post

Relativity is a basic ingredient of perhaps half of modern physics. As such, it is hard to pinpoint particular applications. I would imagine that none of our nuclear physics would work without relativity. You tend to have the kinetic energies where non-relativistic physics fails to properly describe particles, there. In this sense, you could probably add nuclear power generators and certain forms of tumor treatment to the list. However, note that the involvement of relativity may be much deeper in these cases (and hence less obvious), since it is a form of relativistic physics. In GPS clocks, you rather do a non-relavistic calculation and only add relativistic correction terms at the end (at least that's how I would imagine it). So there, the involvement of relativity is much less fundamental, and therefore easier to understand and pinpoint.

Fatalities rates from the summation of two vectors are negligible.

Hi Purephysics, I sometimes tend to have a private life on weekends (and deadlines at work during the weeks), so apologies for replying a bit delayed despite being asked directly. I am not sure that I could properly define "minimum affinity". I mainly wanted to express that I disagree with the notion that a sufficient amount of effort put into physics can compensate for any amount of lack of talent. I believe that even with a lot of effort a person completely unable to cope with school math will not become a successful physicist. At least not in the real world. I simply don't see how you should learn the university curriculum when you don't have anything to grasp on. And especially in the first semesters there only is school-like math. I also find it hard to imagine that someone could develop an interest for undergrad physics and not have some familiarity with or interest in the process of translating a situation into a mathematical model, treating the model with the known math, and extracting conclusions from the result. To make that clear: I'm not saying one has to be the school's math guru to start going into physics (even though that probably helps and is more the norm than the exception in a (German) physics course - at least in my days past). I also do not equate above "affinity for math/logic" with an interest with the teaching in school or particularly good grades. Many physicists found school boring, and only this month a friend of mine, who says of himself that he wasn't particularly good at math in school, finished his PhD in mathematical physics. But a person that for example consistently has serious problems solving so-called "text-exercises" (meaning math questions at school that come along as a text rather than "5+4 = ?") has, in my opinion, little to no chance to succeed in a university physics course. Note that it is not my intent to talk you out of becoming a physicist - I don't even know you. I tend to disagree with the "no natural ability but natural interest" notion. I certainly understand the reasoning behind it, and really like it from the social aspect. But to me it seems to be just that: a reasoning. On the side of hard facts, and admittedly overshooting the question at hand, I haven't heard about a talented physicist with down syndrome. When I speak of "affinity" in above, I find it pretty irrelevant whether you translate it with "interest shown in the past" or "natural ability that showed in the past". I did in fact use this supposedly neutral term over "skill" or "ability" on purpose. Anyways, let's assume that there are only "natural interests". That just makes the whole issue about a minimum affinity, in this case a minimum interest, even more dramatic: If interest is all that matters and a person has already demonstrated a lack of interest, then it very optimistic to assume success in the future. A few unsorted comments on the rest of your post: An engineer is not a physicist, and in some cases this really makes a difference. I'm not sure how this related to math requirements for being a successful undergrad student. In any case, you should perhaps ask him whether he meant "terrible compared to an average engineering student" or "terrible compared to an average school kid". I'm not trying to say I am right. I can only give my opinions based on my experiences of having been a student, knowing a lot of students, having been exposed to tutoring at different levels, and to a lesser degree having followed the "careers" of my undergrads during my time as a PhD student. I certainly do not have any solid sociological data to back up anything I said - and neither does anyone else participating in this discussion. Anyways, while I have not been more in-depth in above (owing to a lack of pinpoints for discussion), I have at least been more broad. Hopefully, that is also to your liking, even if my opinions may disagree with yours. P.S.: after more than an hour of writing above text I am really glad this isn't Wikipedia. It's nice posting without being afraid of an editing conflict

If you're not a straight A student in math in school then physics is likely not the best thing to study at university. It's quite generally acknowledged that most students struggling in a physics course have problems with the math, not with the physics. I also tend to disagree with the notion that a lack of skill can be compensated by a sufficient amount of hard work. I believe that a certain minimum affinity to math/logic is required. In fact, I have advised a 1st semester student to reconsider his course choice in that past, based on his lack of math skills he showed in the class I tutored. And despite this being a very uncommon thing to do (for some strange reason it's considered more polite to just watch people run into their certain doom than to tell them that they are over their head), I still believe it was the correct thing to do.

Black letters and the university logo.

Not really.

Helping rich kids to get better math grades in school? That's quite a huge market in Germany, and "my technical knowledge" sounds as if you may have some math skills, at least. (you've added pretty little details about your skills or interests; only that you fancy pole dance dresses)

It's unlikely that your ideas will change any perception other than yours. The "I have the answer" market is rather competitive.