Relationship Definition and 999 Threads

Hi. This is currently an academic question - I don't have a 'spare' motor to risk at present :) Would NOx catalytic converters become unnecessary on a 'spark' engine if only relatively cold air was made available at the intake? My thinking is that NOx formation needs high high peak temps and...

If you are in the southern hemisphere in winter and the South Celestial Pole has an altitude of 20 degrees, what is your latitude on earth?

The 4th derivative of a sine wave is itself. This, of course, not only is a fact, but can be used to define the sine wave. My question is, are there any theories relating the abundance of sine waves in QM to the fact that the largest dimensions of space-time are together 4 dimensional? For...

I want to give advice! where are all your relationship problems?! man! people here are all too balanced! there's not been any new relationship problems or questions or requests for advice/opinions in ages! bored!

Homework Statement Prove that for any m x s matrix A and any s x n matrix B it holds that: rank(A) + rank(B) - s is less or equal to: rank(AB) The Attempt at a Solution Obviously, the following are true: - rank(A) is less or equal to s, - rank(B) is less or equal to s, -...

I really understand most of the question, just having trouble with one part, so I am going to try to sum it up. if you need more info to clarify please let me know... background... nielson media research provides two measures of television viewing audience (in this case for the world...

I just got handed an assignment to document our database tables. I would rather not have to do this manually and I'm wondering if anyone knows of any freeware that will allow me to create diagrams of the tables and relationships between the tables.

hi , every one! I have a problem with a sphere rolling on a fixed sphere. My problem is to find relationship between coordinate of center of sphere (X,Y,Z) and orientations (alpha, beta, gamma) or Euler angles of sphere. as we know a sphere has 6 DOF in space (3 coordiantes and 3 rotation) when...

http://wimp.com/saganwanderers/

So fundamental point-like particles are expressed by the vibration of a string... yet a string is two dimensional? or even more? How can quantum mechanics not apply to strings?? I don't understand the size of strings vs the size of the particles they represent? Someone please explain!

Hi all. I'm a 16 year old going into my junior year of high school, getting my IB in Physics...and I've just moved 350 miles away from my hometown to go to this preppy new high school (I am quite excited about the level of education, but depressed because of all I've left behind)... In my...

Is there a relationship between the homotopy groups of a pair (X,A) and of the quotient X/A ? It feels like they should be equal under mild hypothesis. More precisely, I am interested in the case where X is a smooth manifold and A a submanifold. Thx

Hello, if we assume that the wave propagation-speed in a medium is v, does this imply that there is an "upper-bound" for the maximum frequency that a perturbation can produce? Or are these totally unrelated quantities? Thanks!

does Newtons first law discribes Newtons third law.

Homework Statement Say, it is known that E_X[f(X)] = E_X[g(X)] = a where f(X) and g(X) are two functions of the same random variable X. What is the relationship between f(X) and g(X)? Homework Equations The Attempt at a Solution My answer is f(X) = g(X) + h(X) where E_X[h(X)] =...

We have the rate of change of number of electrons with energy directly proportional to the volume in an 3-D potential well. For a white dwarf, the mass is inversely proportional to its volume. If we consider the electrons in a white dwarf to be in such a potential well, dN/dE becomes...

Homework Statement a)If the mass of the crate is doubled but the initial velocity is not changed, what distance does the crate slide before stopping? Explain. b) If the initial velocity of the crate is doubled to 2vi but the mass is not changd, what distance does the crate slide before...

Seen somewhere else: Any comments? Does it really look this way?

I don't know if this is a thermodynamics issue or a quantum mechanics one. It seems like there should be some relationship between the average heat and pressure of a system and the behavior of electrons orbiting nuclei. Does anyone know if there are any observations and experiments that have...

Homework Statement Derive the exact relationship between φ and γ, compare it to your experimental results. Homework Equations Snells law, ni sin (θi) = nt sin (θr) The Attempt at a Solution I have know idea what to do. My experimental value was φ=25, γ=15 thanks

I have been told that there is no interaction between the gravitational fields of the sun and any planet, but the issue continues to stimulate my curiosity. If the Earth orbits the sun at 30km/s, how could anything achieve an orbital speed around Earth at greater than 30km/s without...

Hi everyone, I want to find a mathematical relationship between my head direction and the direction of a camera placed at a distance. The objective is to make the camera heading to same point where my head is looking at. Both my head and the camera are in the horizontal plane and the motion...

I have a really fundamental problem with understanding relationship between force & power. Please help me with this example: An electrically powered spaceship (e.g. 100% efficient ionic engine) is traveling through space. No external forces (like nearby stars) act on it. We turn on the engines...

Homework Statement See Figure Homework Equations The Attempt at a Solution I honestly don't know how to start this problem, I tried cutting out the current source and I'm thinking I should get something like a voltage divider. Does that help in any way? A slight push to get...

Hello, Let X and Y be two spaces equipped respectively with two metrics d_1 and d_2, and let's consider a mapping f:(X,d_1)\rightarrow(Y,d_2) How can I formalize the fact that for any point x in X, all the points that are "very close" to x (respect to the metric d_1) must be mapped into...

First post. Hope I'm doing it right. So, I was puzzling through some of the very basic ideas of quantum physics and special relativity and I came up with an unusual place where they might agree. Special relativity states that every frame of reference is as valid as every other one. That...

Ok. There are 2 universal beams. One is 500mm deep and the other one is 400mm deep. For both beams, the top and bottom flanges are 200mm wide x 10mm deep. [SPAN of the beams is not given] Questions is..If the maximum bending moment capacity of the 400mm deep universal beam is 200 kn.m. What...

in general, how do we show linear relationship over a small x of the equation? Is the equation being able to be Taylor expand show itself as linear? likewise can we consider the series expansion at about x=0 (maclaurin series) to be linear too? If not, is there any examples countering...

I have read some books about quantum physics.There are about too kinds of interpretation about uncertainty relationship.The first is that it consists in single measurement.However the other one is statistical explanation that it just consists in measuring repeatedly.I support the former...

Homework Statement Just a proof that I am having touble with State and prove the relationship between the coefficient of friction and the angle of friction The Attempt at a Solution I wouldn't know where to start, I know that (the reaction force X coefficient of friction) = Friction...

Are mass and density always in a 1 to 1 relationship? For example, can there be a material that takes up more space without it having more mass than another material that takes up less space? Thanks, Jake

Homework Statement What is the relationship between Wavelength(λ) and Amplitude?Homework Equations V = fλThe Attempt at a Solution Well, i know an increase in frequency will cause a higher pitch, but what happens when the wavelengths increase of decrease?

Hi, I am going through my notes trying to get things straight in my head and something is confusing me. I also have the feeling it will turn out not to be very complicated, which is why I am a bit frustrated with this. I know that there is something used in general relativity called the...

Homework Statement In space-time when one "travels" a distance x from a point (within the light cone) this, in effect, comes off the time it takes. This is a hyperbolic relationship Homework Equations tau = SQRT[t2 - x2] We'll stay with one dimension (x) The Attempt at a...

Im trying to find a formula(s) that link current to resistance to the heat produced by the resistance, simaliar to a heating element only it would be a liquid or aqueous medium

When you go across a period the radius generally increases. Does that mean that the z effective decrease? If Z effective is the strength (pull) the valence electron feels, that should be the case, shouldn't it? The electrons in the lower n-orbitals should screen it from being pulled to the...

I need some explanation to what I must know in order to solve the next problem. A step by step process and mention of the particular concept I must know would be greatly appreciated as I must learn how to do this by june 8. " In the alpha decay of a Uranium-238 nucleus, what is the ratio v/V...

learning calculus here. got differential calculus, though it is a little foggy, and most of integral calculus, which is a little foggier. also using very unpolished precalc background, though i did give most of it a once-over. i have many questions which i can't think of, but of the top of my...

[SIZE="2"]Moderator's note: two threads merged into one. -- Redbelly98 Homework Statement what is the relationship between the launch angle and the displacement of a projectile, is it possible to say that the launch angle is proportional to displacement, can it be done mthematically by...

Homework Statement I'm struggling to understand the relationship between the Debye temperature and the speed of sound in a substance. An example problem given is: Estimate the Debye Temperature of Silicon and Lead, given that their respective speeds of sound are 9150 m/s and 1320 m/s. (not...

Hi... We have all seen the equation det(M)=exp(tr(lnM)). I was taught the proof using diagonalisation. I was wondering if there was a proof for non-diagonalisable matrices also.

"if and only if" relationship between them? Hi Pfers, just a little question : If you have a problem of the form "Show that these definitions are equivalent",do I basically have to prove an "if and only if" relationship between them?

What will be the relationship between the midnight line and the international date line when the entire world has the same day? Can I get some hints I'm stomped.

Homework Statement Write an equation in words to show relationship between mass concentration, molar concentration and molar mass and give an explanation. Homework Equations Not sure :/ This one has popped up a few times, A=M/Mr, but as of this moment I am not sure of what the letters...

I currently have a question that i am struggling with it is: Propose a mathematical model in the form of an equation desribing, in general terms, the relationship between a given volume for a cylindrical container and the minimum surface area of material required to make it.. i am...

I'm just a year 12 student with an interest in mathematics and physics, but I have a question (or rather a few) for particle physicists/mathematicians out there. I have read a little about abstract algebra - to about the extent of knowing the definition of a group, its relationship to...

May be it's a stupid question but I can't figure it out. according to Eulers Relationship: ej\alpha=cos\alpha+jsin\alpha on the other hand I have equation: Vt=V0cos wt and it can be rewritten as: Vt=V0ejwt where V is voltage in AC (see link below)...

is interplanar spacing or interatomic spacing directly proportional to grain size?

I was assigned a project in Applied Math and I chose to investigate the strength of the relationship between Math and Physics. My scope of tests is still limited, so I decided to first do a chi squared test (to show independence) and then determine the product moment correlation coefficient...

Hi everybody, Guys I'm a total stranger to physics. I need some help to find the relationship between the major/minor axes of an ellipse and the radius of a sphere in a cone of light. For example, imagine a light source is located at 'h' height from a plane and a sphere(with a radius of...