Concept Definition and 1000 Threads

Can someone clarify the following quote? I consider it quite possible that physics cannot be based on the field concept, i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, [and of] the rest of modern physics. (Albert...

Hi, I have some review multiple choice questions, and some of them, I can't understand why the answer is so. If you could clarify the concepts, that'd be great! Which statement best describes the Earth’s rotation about its axis? a)The tangential velocity is the same at all points on the...

I think I got these right but I wanted to check first before I took my test... The ones that don't have any answers are ones I need help with. Concept Review: 1. Which of the following is most likely to form a cation? Xe Cl Ca S 2. Which of the following is a chemical...

I was asked (on another non physics site) how an observer can measure the speed of light to be the same as someone who is moving away/ towards the light source. I know that it is a fairly simple idea but I couldn't find the words to answer comprehensively. Here is what I wrote: In...

A guy was explaining the concept of Watt to me, using a drawing of a machine that used 1 Joule per second, i.e. an oven. This one watt is now converted into heat, but excactly how much heat does 1 watt equal in terms of temperature? I'm not even sure if there is a relation, but if not, how is an...

I have to make a concept map in Microsoft Word (Not necessarily but that's the only thing I know how to use.) but I can't figure out how. I've done it before so I can't figure out why it isn't working now...:confused: Anyone have any suggestions for making a concept map?:smile:

I hope I'm in the right section. :smile: This is more or less a question about finding some published documents... I'm a little curious about Hestenes' FCI. I've encountered it a few times over the past year through papers and talks about science education, but they only mention its name and...

Hi , I have hard time understanding the concept of vector, matriecs in relation with rank and independent/dependent columns / rows. I have two question that I would like to have help: The set of vectors {v1,v2,v3,v4} would be linearly dependent if 1-v3 is the zero vector 2- each of the...

I saw Doom the movie last night and there was an interesting concept in it. They said that an artificial 24th pair of chromosomes was created to manufacture greater beings, they were basicly far more superior. And I thought, is this possible? Could chromosomes be added or change to make a...

hi there i was just wondering could anyone please explain to me the concept behind a "SWINGING ATWOODS MACHINE"-i mean as to why it works that way!"? I really want to know the concept! thanks fahd!

A juggler throws two balls to the same height so that one is at the halfway point going up when the other is at the halfway point coming down. At that point: Their accelerations are equal but their velocities are equal and opposite. Right?

A ball is thrown vertically upward. Consider the following quantities: 1)speed, 2)velocity and 3) acceleration. Which of these will be zero when the ball has reached the maximum height? Won't all three be zero?

why the concept of tensor was invented. I always see that tensors are provided in matrix format. example inertia tensor is there in a 3x3 matrix. why?

Hello everyone! I'm confused on what I'm suppose to do here, I think i might got it though but i need to make sure... Here is the problem and my work: http://show.imagehosting.us/show/764032/0/nouser_764/T0_-1_764032.jpg he let r(t) = f(t) i + g(t) j + h(t) k. So if i multiply this by...

can ne 1 explain 2 me the canonical formalism of generalising the concept of field in QFT...i m not 2 sure abt the replacement of generalised coordinates q(i) i=1,2,... n with phi(x)

I know that if two people are pulling on a rope with the same force, the tension in the rope is the force that one of them is pulling at because the rope is pulling back or something like that. I don't really understand how this concept works. What happens if they are pulling on the rope with...

not clear on concept Q Two protons are aimed directly toward each other by a cyclotron accelerator with speeds of 1650 km/s, measured relative to the earth. find the maximum electrical force that these protons will exert on each other? K_a + -U_a= K_b + U_b and K_a=0, U_b=0 -U_a=K_b K_b=...

I don't really get the concept of significant figures. Anyone can help me out? 1200 X 23.4 What is that in significant figures?

This question applies with the so called "infinite" pigeonhole principle. Why is it possible to construct a one-one function out of two sets where the codomain has a length smaller than the length of the domain?

I am trying to find the ▲cos x. By using its definition. It simply turned out to be cos(x+1) - cos(x). How do I express this in terms of sine? (and as only one term)?

This question bothers me since ever... At a given time in a EM course, we stop talking of forces relation between two particles and start conceiving electric interaction as something where one of the charges acts upon the whole space and the other, since it occupies some portion of the space...

[(Money) = (2 ^ - 1) ] / [( Time) = (1 ^ - 1)] (2 ^ -1) / (1 ^ -1) = (1 / 2) / (1 / 1) = ( 1 ^ -1) / (2 ^ -1)

Hi, I have come across "air-lock," as a concept to explain decreased flow of fluid in a tube as a result of air bubbles introduced into the system. I'd really appreciate an explanation for why this happnes? is it because air is compressible? is there a text that would recommend as a...

This is a revisit of a site that we have seen in the past, but there has been some updating and it looks promising. This is definitely not what most have in mind when they talk about the internal combustion (re. Otto/Diesel cycle)engine and list the limitations of it. In fact, it's not even...

A New Perspective of what Gravity really is? A New Perspective of what Gravity really is? We all know how Einstein showed us that flat space is warped when matter is present, and that the more matter there is, the more warped space becomes, this showed us that the further you are into the...

Hello, I'm new to the forums here but I just wanted to ask a couple of questions. Is the theory of Relativity unique in its proposal that space and time are interwoven? Basically, was it the first theory to make such a claim that there exists not only space and not only time but spacetime...

My first post here is going to be a question. Hopefully you guys can help clear this up. I simply have been unable to grasp the concept of voltage. I know how to calculate it and all but I can't grasp it. :bugeye: I know that: Couloumbs : the actual amount of energy Amps : speed...

in einstein's famous gravity model - gravity is caused by a disruption of some fabric by an object with mass (i.e. the ball on the fabric causes the fabric to "expand" creating an inward force toward the ball for other objects). i was thinking about this and wondering the following: 1) if...

Hey Mathwonk, just a quickie. When I think of a differential, it is written as y=y(t), and dy= dy/dt * dt. When I see this, I think of it as we want to deal with only the variable y. But y(t) is a function of t. So we set y=y(t), so that y is a variable by itself. As a consequence, we usually...

So what do you people think? What are the arguments for each?

A pole of scientists gives a surprising variety of opinions: Address:http://www.spiked-online.com/sections/science/sciencesurveyA-B/default.htm The one that stood out to me, in the context of PF, was: "Science is disputative." Alot of people echoed Feynman's answer to this question...

If E(cell) = E(cathode)-E(anode) and E(cell) = (RT/nF)ln K Then shouldn't E(cathode)-E(anode)=(RT/nF)ln k ? I have a question asking to find the voltage of the cell and I am given a equilibrium constant... which means i should use the second equation with "k" in it, and i get the...

I'm having trouble understanding the concept of laplace transformations. my book states that it is comparing how much a function y(t) is like a standard function. what exactly does the answer mean such as y(s)=1/(s-2) is this the differnence between the functions depending on the value of s...

Can someone explain the concept of recrystallization in metals to me? I'm having some trouble understanding what actually happens in the material during this process, and also what causes it to happen...

i hope everyone's in fine health in this fine thursday evening. :approve: ok i just had some general questions on atomic masses, and to the chemists in here, i appologize if these questions are a bit too basic for you. :cry: but ur help and time is greatly appreciated nonetheless! :smile...

If we want to prove any equation. How we come to know that when and where we have to put the value of this or that formula or when and where we use this or that formula? e.g. (Derive an equation which shows that the absolute temperature is directly proportional to the average translational...

The concept of "Rotation in 3-d" in QM I'm having difficulty with two ideas and wud appreciate some help: 1)commutation relations: [L_i, L_j]=i\hbar\epsilon_i_j_kL_k reflect the law of combination of rotation in 3 dimensions. What is the this law and why must in be satisfied...

Quick concept question! Ok, How does the current relate to the speed. So let's say everything is normal and if I reduced the speed by 1/3 what would happen to my current? Thanks! :cool:

Hi, Its been a number of years since I've actively studied physics, and I find my knowledge extremely lacking, however there are some fundimental concepts I seem to get lost in and would ask for some (polite preferably) assistance. My problem is with regards to dimensions and our (or my...

It is known that a tensor field is a tensor-valued function T=T(p) whose argument p is a point of some space (or some manifold). However, in physics some tensor fields are produced from other tensor fields, e. g. Lagrangians in physical field theories including tensorial fields...

How much energy is given out by one man? If he applied a F on a object, friction is f, distance is s. What's the energy given out by him?

I am new at here at PF and originally posted part of this in an inappropriate forum then added a few words and moved it here but didn't like it as it read so I deleted it and started a fresh thread. I was very tired and about to drop one night when I had a strange thought about where did...

Last we were introduced to the concept of entropy in school... I was quite suspicious to it already at first sight.. It is something like that in a closed system, chaos always increases... meaningen that universe is heading towards chaos... (i.e. universe is heading towards where materiai...

Thougt of a thing, reading a topic about dimnesions... if we think like this... a point had 0 dimensions... there are infinite many points in a line (which has 1 dimension) there are infinite many lines in a square (which has 2 dimensions) there are infinite many squares in a cube...

I want to share and discuss with every forum posters here a new concept on piston heads, which by the way is not as brainy as you may think. The new concept is concerned with spark ignition engines. Everybody know that combustion process have two main stages in this kind of engines...

Hello everyone, Today I saw some waves in my physics lessons. A stone drops into water, and waves are created and spread from source to surroundings. Finally, the water became calm again. What's the most proper explanation for that? I think: Water molecules gain energy after being hitting...

A negatively charged rod is brought near a suspended metal sphere. The sphere is 'grounded' by touching it with a finger. The finger and the rod are now removed. What charge will be on the sphere, positive or negative? Explain what happens. Initially I thought that the finger would remove any...

Consider a long conducting rod that is suspended by insulating strings. Assume that the rod is initially electrically neutral, and that it remains so. The rod is positioned along the x axis, and an external electric field that points in the positive x direction (to the right) can be applied to...

Consider the concept of a gyroscope. You tie a string to one end and attach the other end to the ceiling so only one end is supported, If you let go when it is not spinning, the obvious occurs - it falls from its horizontal position to a vertical position with the other end pointing towards the...

i am ineterested in complexity concept do u know any introductory documan on net ...