Stupid Definition and 300 Threads

probably a stupid question! on force. when we spin round and round we feel dizzy,when we move in front we dont,now considering in both cases a force is acted on body,one force has an effect on your brain where as other does,so what is so special in this circular force that makes brain...

Is power given by \vec{F} \cdot \vec{v}, or just Fv? I'm thinking it can be both if the velocity and force vectors are parallel, but I'm not sure...

I don't understand one think: when we calculated the correction of the magnetic moment of the electron, we consider only the finite terms of the vertex correction that non depend on the parameter μ. Using Ryder notation , we consider only \bar{u}(p')(γμ+\Lambdaμ(2))u(p) but there is also...

I did not understand one thing: imagine we have calculated a cross section relates to a process, for example compton scattering. The parameters (charge, mass, ...) that come into play in cross section are "bare parameters"? Then after the renormalization of the theory, getting the "bare...

Ok guys, first of all I apologize if this question is not worded correctly, is in the wrong section, and for any other thing that may be wrong. I am not a scientist, physics is merely a topic I enjoy learning about. So here's the situation.. I have this co-worker who fancies himself a brainiac...

I have a question, and I'm positive it has a really simple answer, but I can't think of it right now. In the infinite square well (the simplest bound problem), the wave functions have discrete energy values. We can have a wave function that's a linear superposition of any number of these so...

making stupid mistakes during research - "ettiquette" Hi, I have been doing research this summer, and I have been making a lot of stupid mistakes that my adviser has to correct me on. For instance, a graph does not go to 0 where it should due to a preceding function w/zeros, different math...

I've always been the type to get the concept perfectly yet make some stupid algebra or general time based error on the tests. All through my schooling career, stupid mistakes have dogged me time and time again. I never took a proper algebra course(long story involving Christian fundamentalism...

Years ago (I'm talking 20 years or so) I saw something on TV about the human genome project. The narrator was Asian so it might have been Michio Kaku. Anyway, I recall him having said that humans have all the genetic instructions needed to make all the other animals, while none of the other...

Hi, I don't understand how this can be so difficult. So I have a [char ** ptr] pointer that stores a list of arguments. I'm able to PRINT each of them by doing printf("%s\n", ptr[i]) But how the heck do I is strcmp to see if a certain argument is there? Apparently I cannot just do [if...

I attended a theistic high school and did not receive much of an education on the big bang theory. My question is was there any sort of matter or energy at the start of the big bang, and if so where do scientist hypothesize its origin?

Homework Statement B = variable magnetic field, of constant direction (e.g B = b cos(wt) N, where N=const vect) A = magnetic potential vector of B R = vector from some origin O to a point M It is assumed that no exterior electric potential is present. Problem: to find the...

If I see an expression like \sqrt{E^2c^2} I can just remove the square root sign right and replace it with Ec?

This question may seem a little ridiculous... I have not taken a course on relativity (I did get a bit of an intro in modern physics class) so maybe that's why I thought of such a crazy thing. Anyways, here it is - What if objects that move fast in our eyes aren't necessarily moving faster...

Suppose you theoretically have two betatrons each accelerating a particle near light speed in opposite directions. Suppose you collide both of these electrons together head on both at close to light speed. Since the collision is happening at speeds over the speed of light, does anything peculiar...

I am a 2nd semester freshman in college, and I am absolutely sick of making dumb mistakes on tests! For my first 2 tests this semester, I've received unsatisfactory grades because I messed up an integral here or added something wrong there. I feel like when I get to a test, I cannot think...

I have been reading Ordinary Differential Equations (Pollard) from Dover. The chapter I am in, is called Problems Leading to Differential Equations of The First Order - Geometric Problems. Problem : Find the family of curves with the property that the area of the region bounded by the...

Thread title says it all. Lets say you have an indestructible jar. The jar contains two biscuits. Now imagine you had an infinite number of these jars, each containing two biscuits. Would you have more biscuits than jars?

Hopefully this question hasn't been asked here before, I did a search and it seems everyone else is asking much more practical questions. Anyway...The Situation: I'm modifying a Nerf gun (this one for anyone who's curious)...

I read in a book that since the area of a black hole increases, the entropy increases, so black holes are consistent w/ the second law of thermodynamics. So...I have a really stupid question on black holes and the second law of thermodynamics: Consider an ideal gas of non-interacting...

Newt Gingrich: "Child labor laws are stupid" http://www.latimes.com/news/politics/la-pn-gingrich-child-labor-20111121,0,6466282.story Please tell me this is a parody or I'm misunderstanding him or SOMETHING. Cause the way I read it, he wants to repeal CHILD LABOR LAWS.

How does the theory of probability work in an equation whose parts are additive infinities of different powers that are in randomised changes in the infinities powers? written example infinity to the first power infinity (both infinities are the same infinity but the resulting infinity would...

Homework Statement A = 2i + 3j B = -5i + 6j Calculate (draw vector diagram) A + B A - B Homework Equations actually we're just confused as to whether we need to use the angles to answer this or just answer it directly, meaning that for A + B the answer would be -3i + 9j The...

http://imageshack.us/photo/my-images/809/equationu.png/ I'm not understand this simple step. Btw, this isn't technically a homework question so I think it should be fine posting it here. Thanks

I don't know why I thought in this way , I ask : if a and b are real numbers and c is also a real number , now if a=b why a+c = b+c , and also why ac=bc , questions like this I don't know why I am asking , they seem to be stupid . What = means exactly . I know that numbers themselves are sets ...

Homework Statement The question goes: A meter stick with a speed of 0.8c moves past an observer. In the observer’s reference frame, how long does it take the stick to pass the observer ? Homework Equations Special Relativity: where T and L = proper time/length, t, l are not: t =...

my 16 year old cousin always get me into trouble.. the story goes like this.. we go to school together and my aunt keeps on telling me that keep an eye on him (he is 16 and I'm 17).. i lie to my aunt to cover him up.. like the other week, my cousin went home late and he told my aunt that he...

I spend a lot of time searching through random videos on YouTube. I always find such pointless videos. Post pointless videos that you've found. Here's one (of the many) I've found:

Do many men just look for looks in women first and then see if they have anything else in common? Is it the same for women? What about YOU?

Homework Statement Do you round an answer up as you go along in a problem or do you use the full until the last final answer of the problem. What happens when you calculate an angle, do you round to the nearest degree or can it still be allowed as a decimal? Sorry this question goes back...

I understand that matter and energy bend space time, yet i am curious as to the level at which it requires to bend it. This is obviously an elementary leveled question, but i am quite curious. Also, is there any level of matter that is incapable of bending space-time? Thank you!

1. There is gas tank, contains 5 liters of CO2 under pressure 14.7 MPa, temperatute is 300K. I try to calculate, what temperature gas will have after release (to atmospheric 0.1 MPa and 2000 liters volume). But I cannot :( 2. volume * pressure / temperature = const The Attempt at a Solution To...

Hello! I study mathematics and am in my sixth year, but... I have a very elementary question: I stumbled upon it while learning for quantum mechanics. But it's nothing new, it's happening to me all the time: I get confused by things like this! Observe the following facts: Suppose we...

I have a stupid question to ask you all. Let's just say that you shut your door, and then shut all your windows so there isn't any ventilation and stayed in your room for several days. Could you end up breathing until you've reduced the oxygen to dangerous levels?

Hello everyone, I am here again to ask something, though maybe silly to be raised, to obtain a clearer picture of why exactly we are implementing the SMPS in the way we are doing. Let me list them to save your time in reading: Don't bother to answer them all, it would be my honor to have...

Here's my stupid question: In the mass equation from SR, we have the m0 term for rest mass; but how would you determine the rest mass of an object? Isn't an object on the earth, which is in motion, also in motion? So wouldn't the mass of an object on Earth not actually be its mass at rest...

This may sound stupid but I have always wanted to know what exactly fire is. So can anyone tell me what it is?

I'm trying to learn DE independently, so if this is insanely stupid, try not to make me cry. :) \frac{dy^2}{dx^2}+d\frac{dy}{dx}=x dy^2+dxdy=xdx^2 (y + C)dy+(x+D)dy=(\frac{x^2}{2}+E)dx This is the line that gives me the incling I'm way off... this could be what is below, or could simplify the...

Like the title says... I should be way past this (in ODEs+Lin. Algebra). I'm just really tired, have a final tomorrow, and cannot for the life of me understand why this works out the way it does. Here goes (and please show most steps, it'd be greatly appreciated, thanks): Start out with...

i am an idiot. i am going to drop a rock from the top of a building. i want to know the force with which the rock will impact the ground. i know the rock's mass is 1kg. i know that the rock will accelerate at 9.8m/sec/sec. if i use the equation F=ma, i get a fixed result/answer - 9.8N...

Hi all, So I am applying for Ph.D in a few universities. In the application form I am asked for my ethnicity. I am an Arab (Egyptian) but I can't find such ethnicity in the list to choose from. What should I choose ? I think I am not black nor white and definitely not Asian or Hispanic...

Homework Statement Before I state my problem, I need to quote this from my book http://img18.imageshack.us/img18/3748/comparisonnr.th.jpg Uploaded with ImageShack.us http://img806.imageshack.us/img806/8665/integraltest.th.jpg Uploaded with ImageShack.us See the problem here...

stupid forces of friction ! [b]1. a force of 36N is applied to a 6kg cart. If the cart accelerates at 5.5m/s what is the force of fricrion im not even sure what to do, I am in physics 20 and not very good at it please help this is my atempt Ffriction=Fn*u idk what anthing means...

I've haven't taken a chemistry course as of yet, so I'm probably getting something very wrong here, but one thing that someone said confused me. They said that when an electron changes it's orbital, it emits a photon. I like to think about orbitals (and I know that this is ONLY a useful...

i know its a stupid question but I am a beginner: according to eisntein: E=K+m_{o}c^2 but the plane wave solution yields that particle's KE is its total energy,where free particle has no potential energy. But where is the rest mass energym_{o}c^2? Is it omitted?

[PLAIN]http://img560.imageshack.us/img560/6712/fizika5.jpg Homework Statement The electric energy is used to heat the liquid in the metalic bowl.. 1.Why is the liquid warmer at the top of the bowl than the bottom? 2. Why does the liquid's temperature raise faster if the metalic bowl has...

Won't Compile the simplest of programs! Am I being stupid? Hi, I'm just getting my teeth back into Fortran 90 I had a course on it last year, and just want to familirise myself with it before I apply for post grad stuff. Anyway, the program i have written is: program emosix real:: a...

This is a question that was brought up in class...we were jokingly talking about if everyone in the world was transported to North America, and if all those people jumped at the same time, how the force would impact our orbit. So we estimated the mass of about 6 billion people versus Earth's...

This isn't homework, just an example in the book on how induction can easily be used wrong, but I am having trouble finding exactly what the problem is with what they did, I know it's obviously not true: Claim: If n belongs to N (the natural numbers), and p and q are natural numbers with...

Homework Statement If G is a finite group with m elements. Show that a^m=1 for all a\in G. Homework Equations order of group equal order of elements. The Attempt at a Solution i know order of group equal order of elements, but how to give a detailed proof? Is G cyclic?