timo

The key to your problem is using the fact that [math] \sqrt{xY} = \sqrt{x} \cdot \sqrt{Y} [/math]. Using that, try to pull out as many factors as possible. I´ll give you a first step, you´ll have to do the others yourself: [math] \sqrt{75a^2b^3c} = \sqrt{b^2} \cdot \sqrt{75a^2b^1c} = b \sqrt{75a^2bc} [/math]

Is that a different display system than the decimal one or is that [math] \sqrt{75 a^2 b^3 c} [/math] ?

Could this something be the "some stranger I met told me <add something here>. Could you complete strangers I´ve never met take a look at <this thing from the last sentence> and tell me if I should trust this stranger I met?"-baseline of the initial post ? I like it. "Relativity is wrong" for everyone!

So the message is: "There is a muslim country in which people show less belief in evolution than in the us?"

Erm ... Phil? How is your quote a response to what Alice said?

Imagining flat 4D is simple. If you´re out for a date you agree upon place AND time. Curved 4D, yes, I think that´s pretty impossible to imagine. Luckily, physics is about the governing laws and equations, not about imagination ... I´d have to think a moment whether attractive and repulsive are properly defined in an arbitrarily curved spacetime, so I cannot really answer that. But e.g. Dark Matter which is in agreement with GR causes "distances" between points to increase with a positive "acceleration". So losely speaking, you might have what you call anti-gravity there. Imho, starting to learn differential geometry and GR would be a great starting point for trying to understand the not-yet-defined concept of "anti-gravity within the scope of GR". GR actually isn´t as hard as people normally think. It just nessicates to give up or generalize a few concepts familiar from linear algebra.

I think you are taking the pictures about the sun lying in the middle of an elastic membrane too serious: The dimension that the membrane is deformed in (down) doesn´t exist (4D curved spacetime is not embedded into a higher-dimensional flat space). So you´d have trouble defining the "opposite way to which it is normally warped". In fact, strictly speaking your question would become "within GR, can spacetime be warped differently that it is warped within GR", anyways.

A definition for the term "anti-gravity" would certainly be a nessecary condition.

The 2/3 in the exponent is wrong, didn´t check the rest.

That would pretty much fit my usage of the term, although I´ve never bothered about a strict definition. The elementary fermions are the quarks (up,down,strange,charm,top,bottom) and the leptons (electron, tau, myon and their respective neutrinos). Fermion, actually. But notice that protons are no elementary fermions since they consist of quarks and gluons (and would still be matter by above definition). Might depend on the framework you´re working in and what you´re currently calculating. For the framework of the standard model where the definition of the elementary particles stems from the answer is no.

I doubt that the solid-state guys had exactly her in mind when they read the name of the file on the print-queue. We had to find excuses for using their printer, so I didn´t explicitely ask why the filename raised the attention. Naturally, I honor all collider-predictions which proof or rule out certain models - even if they are made with the wrong event generator . Even if they just narrow the available parameter-space of proposed models, that´s already fine. In the case of strings, however, my impression (which is totally taken out of thin air and certainly influenced by the bad reputation string theory has here) was that the parameter space of possible string models seems rather unlimited. This of course reduces the value of an exclusion-statement to ... well, in first approx to "parameter space excluded over parameter space avaliable equals zero". I defenitely can´t judge about the relevance of the paper for string theory and less for lqg. But I could at least read and try to understand the paper. EDIT: At least this one was printable on the theory-printers

I cannot recommend looking into her stuff, anyways. I remember blocking the printer room of a neighbouring institute for several hours by printing out a rather long paper of hers (our printer here refused printing it at all). This illegal use of institute-printers for the purposes of non-members (=me) would have gone unnoticed if not for those sexually understimulated physicists who had to find out what this "joanne.pdf"-job is .

By that I mean that F = C/r², where C>0 is a constant which will cancel out in your case. Therefore, it´s exact value is irrelevant. However if this is homework, it might be better using the full term for F (the force due to gravity) because showing that everything except the dependence on r cancels out might be part of the assignement. Here´s the full term: http://en.wikipedia.org/wiki/Gravity#Newton.27s_law_of_universal_gravitation

Weight F as a function of distance r from the center of the planet goes as F ~ 1/r².

Isn´t it rather you walking by without noticing, especially if they are like you?

If the people are competent enough to decide what´s worth publishing they should also be able to give you advices where and how to do so. After all, "publishing" can have quite a wide range from "put it on your homepage" to "send it to a peer-review paper". The people you talked with will know better what they meant by publishing, I think.

You´re right. That´s effectively what I said, in case you didn´t correctly understand me. Swallowing is done by some muscles in your throat. You can simply test that by swallowing something with your head down. Let me say this in advance: The question was not in my original list. It´s just that someone asked for a statistical question and this one was the first one that came to my mind. For the answer: You´d better sit down and calculate the result rather than to rely on your intuition. Intuition often is a certain way to get statistical questions wrong. To some extend that in fact is something that someone who has a basic education in math should know.

Whether anatomical details like the muscles swallowing the food are something that you should really know after high school (and the question whether it´s a detail or basics) should be for others to decide. But keep in mind that if I understood the purpose of the questions correctly, it´s not about tricking people but about giving at hand a checklist to test very basic knowledge which everyone should have.

LHC has two operational modes: The proton-proton mode which is the 14 TeV, and a less famous heavy ion mode (the lead) which is at higher center-of-mass energies. Dunno the value there but the 10^6 GeV will probably correct. Edit: It is: http://public.web.cern.ch/Public/Content/Chapters/AboutCERN/CERNFuture/WhatLHC/WhatLHC-en.html

You don´t really need much thermodynamics to correctly answer the question. And it´s no trick question at all. Also, from my understanding people should be able to correctly answer the question in the sense of also understanding why a particular answer is correct, not in the sense of correctly guessing it. For example in my question 2), I´m pretty sure that almost everyone will have the correct answer while much fewer will have the correct explanation (where the correct explanation is much more important there). To some extend, question 2) is the trick question

Here goes one (although it´s pretty popular so many people will already know the answer): In a TV show, there´s three closed doors. Behind one, there´s a prize, behind the others, there´s nothing. As the candidate, you may chose a door and grab whatever is behind it. After having chosen a door, the moderator will open a door behind which is nothing - regardless whether your choice was the prize or not. You are then allowed to rethink your decision and chose the other remaining door: a) Yeah, that sounds like a good idea. b) "No way, my chances of winning are better if I stick with my original decision" c) Who cares? The chances of winning the prize are the same for both remaining doors.

Never went to High School but here´s two questions that spontaneously come to my mind that anyone with a basic education should be able to answer: 1) On a hot summer day, you come up with the idea of leaving the door of your fridge open to cool the room. What does this cause? a) The room will indeed be slightly cooled down b) No change in temperature but your yogurt starts walking away. c) That just heats up the room even more 2) Can a massive particle accelerate with the speed of light c? Why/why not ?