Approach Definition and 565 Threads

Homework Statement Simplify the following: \frac{\frac{1}{\sqrt{t^2+1}}-t^2(t^2+1)^{-3/2}}{\sqrt{\frac{1}{t^2+1}-\frac{2t^2}{(t^2+1)^2}+\frac{t^4+t^2}{(t^2+1)^3}}} Homework Equations The answer in the book was: \frac{1}{\sqrt{t^2+1}} I didn't believe but then I graphed...

I was wondering how'd you find out the highest safe approach speed when going through an intersection. P.S. Could you please explain in detail. Thanks !

Sphere melting/freezing timescale--scaling (simplest approach)? Hello everyone: I am new to melting/freezing-type behaviour. I would like to calculate approximate melting timescales for spheres (uniform composition) thrown into a hotter liquid. The spheres would initially be at a lower...

Homework Statement What is the distance of closest approach in terms of the impact parameter and the limiting value of the speed as r tends to infinity? Homework Equations N/A The Attempt at a Solution This is not a h/w question, it's an equation I need to do my h/w...

Mostly I have little interest in this topic, but the discussion came up in a recent thread about what is the axiomatic basis of GR? I threw out what I would consider a 'physicist view': the action or field equation plus rules for relating mathematical object to natural objects are all you need...

The "right/logical" approach toward Education? For those who are interested in attempting to understand the nature of reality, wouldn't it be undeniably correct to try and discover how to prolong the human lifespan or attempt to find a theoretical solution to the problem of aging?- seeing as...

Link to guy's blog post: http://ftlfactor.com/2011/04/23/how-does-special-relativity-allow-effectively-faster-than-light-travel/#comment-117 He says he has a PhD in space physics. My understanding of special relativity was that the speed of light is always constant no matter what...

Hello, I am just curious. Latent heat and its characteristics are classical approach right? Its by all means classical? Does quantum approach or something like that exists? Can anybody give me directions, or some terms... Thanks

http://www.stewartcalculus.com/data/CALCULUS%206E%20Early%20Transcendentals/upfiles/projects/ess_wp_0205_stu.pdf I'm sure this question has already been asked in some form so if I'm repeating, my apologies. I’m not looking for an answer (not trying to have others do my work for me). However...

I was asked recently to prove that if N is normal in G: G solvable iff G/N and N solvable. now, I was able to do so, but I wasn't very happy with my proof. ==> the way I approached this was to form the images of the Gk/G(k+1) under the canonical homomorphism G-->G/N to prove G/N...

Hello Can someone tell me basic equation of car engine temp. that depends on load. I don't need a precise equation - i need something simplified for simulation.

Problem is: given the distance of closest approach in a coulombic fields is: d=\frac{1}{4\pi\epsilon_{o}}\frac{Z_{1}Z_{2}}{mv^{2}} calculate the distance for two protons with velocity v=3X10^5 m/s and mass m=1.7X10^-27 kg Can someone please advise on whether I should plug in the mass...

Hi, I'm struggling to understand how to approach set theory equality questions for example: True or false? (A n B) is a subset of (A u B) Is quite simple as its obvious the intersection will contain everything that is in the union But what about a more complex question like ...

I have recently stumbled into this problem trying to visualise a certain economic model and I'm finding the solution is just beyond my reach. As far as I can tell there is a simplification of the problem which is easier and would still be good to have answered. There are two moving point...

Which of the following is the most promising road to quantum gravity? 1. quantising General Relativity 2. quantising a different classical theory, while still having general relativity emerge as a low-energy (large-distance) limit. 3. having general relativity emerge as a...

This seems to be a very interesting low-tech system to harness solar energy. I would greatly appreciate any input, critical or supportive, from the many knowledgeable posters who frequent this forum. You can click on the link and watch a short video, or just read the description of how it works...

how do you name a circle? Obviously you could name it by its centre example a circle with centre at O would be called circle O. but what if you have two concentric circles?

I have two sets of line segments, A and B. My goal is, for each segment in A, I want to find all segments in B which approach within some threshold distance. Clearly this can be done in O(n^2) easily enough, but I think it's possible to do better. For instance, if I were working with points...

Hi everyone, I was wondering if 2 unlike charges are placed a certain distance d apart, they will attract and move towards each other and the attractive force is given by Coulomb's kq1q2/r^2. Since r cannot be equals to zero as it would imply that the 2 charges exist as the same point in...

Homework Statement What is the pressure difference between points A and B (point where glycerol and air heads meet) in the picture, if d1 = 0.50 meters, d2 = 0.25 meters, and d3 = 0.71 meters and d4 = 0.86 meters. (ρH2O= 1.00 x 10^3 kg/m^3, ρgly = 1.25 x 10^3/m^3)...

Now I'm a 16-year old high school student, and as some of you might know, i like math :) I have been studying the integration by riemann sums lately, and i truly love the logical concept. So I decided to create my own formula for calculation of graph curve length (without looking at the present...

Dear all, here is the new approach how to prove the Fermats Last theorem for the prime powers of n. Thank you all that you have mentioned the Diophantine equations. The proof has still one missing link. It should be proved that l is coprime to (c-b) and the same kind of proof should arise for...

I was attempting a simple graph theory question. "Let G=(V,E) be a simple graph with n>=3 vertices and 2n-3 edges. Suppose that every subgraph with m(>=2) vertices has <= 2m-3 edges. Let S be the minimum degree for any vertex in V. Prove that S is either 2 or 3." So I let A be the...

Hello all, I'll hopefully be attending a cognitive neuroscience PhD program next fall and I'd like to learn some programming beforehand (having programming skills helps for lots of neuroimaging labs) Labs I've worked in used UNIX and MATLAB and I'd really like to improve my knowledge before I...

N. David Mermin has an interesting geometrical approach to SR that I came across today. He seems to have described it in the following places: 1. Mermin, N. David, "Space-time intervals as light rectangles," Amer. J. Phys. 66 (1998), no. 12, 1077 2. a popular-level book called "It's About Time"...

Homework Statement Treating air as an ideal gas of diatomic molecules, calculate how much heat is required to raise the temperature of the air in an 8.3 m by 13 m by 5.0 m room from 24 °C to 27 °C at 101 kPa. Homework Equations PV = nRT ---> n = PV/RT Q = NCpDeltaT The Attempt...

Homework Statement u_{tt}=u_{xx} The Attempt at a Solution Where do I start? I have this wonderful Schaums outline at hand, and by looking at similar (unfortunately unsolved problems) I can guess that the answer will be in the range of: u=F(x+iy)+G(x-iy) I'm saying something in...

"Problem approach" education? Sorry I don't know the exact name for this kind of education in english. One of the Universities I'd like to attend offers a problem based approach for it's electrical engineering degree (I want to become a EE). Basically, you are given a problem every 2 weeks that...

Homework Statement Im taking a dynamics course and I am using The strogatz book Non-linear Dynamics and Chaos I need to solve a problem that is similar to problem 6.1.14 Basically it consist in the following You have a saddle node at (Ts,Zs) which is (1,1). Consider curves passing through...

Homework Statement For my lab, I need to calculate the height of the ring stands so the projectile can pass through them; as well as the angle the projectile will come at them. I have calculated/measured the following things: Muzzle Velocity: 4.11m/s Vix= 4.02m/s Viy= 0.85m/s Delta Y: 0.87...

Homework Statement Hello, I would just like to make sure I am doing the problem correctly. What I have is a cantilever uniform beam that is fixed at one end and free on the other. Basically, it is a wing and I am using a lumped mass approach to find a graphical representation of the wing's...

Homework Statement If for each \epsilon>0 , there is ameasurable subset E1 of E that has finite measure and a \delta>0 such that for each measurable subset A of E and index n if m(A\capE1) < \delta , then \int | fn| <\epsilon ( integration over A) Show that {fn} is tight...

Two cars approach each other at an intersection. One car has a mass of 928.4 kg and is traveling in the negative y direction with a velocity of 21.4 m/s. The second car has a mass of 951.2 kg and is traveling in the positive x direction with a velocity of 39.5 m/s. If the collision is totally...

Why is internal energy not sufficient to compare states? Thank you for your answer.

Homework Statement Two objects 1 and 2 are moving towards each other, 1 along the x-axis and the 2 along the y axis. Initially, object 1 is at (- 28.9,0) (in m) moving at speed v 1 = 13.7 m/s, while 2 is at (0.-36.8) (in m) moving at speed v 2 = 7.5 m/s. How long does it take until the objects...

For instance, let's say that you want to study fermat x^n+y^n=z^n for n=3; do not mind that we already know the answer :-) We could consider the densities of exact cubes, d(n), and then to calculate joint probabilities for d(Z), d(X) and d(Y). The mechanism can be applied, for instance, to...

Homework Statement A block of mass "m" is placed on an incline of angle \theta and mass "M", which is placed on a horizontal surface (the ground) and release from rest. Both the block and incline start accelerate. All surfaces are frictionless. Find the acceleration of the block with respect...

Homework Statement A spring of rest length L_0 (no tension) is connected to a support at one end and has a mass M attached at the other. Neglect the mass of the spring, the dimension of the mass M, and assume that the motion is confined to a vertical plane. Also, assume that the spring only...

I heard that Fay Dowker (Imperial College London) is scheduled to give a series of introductory lectures on CS-quantum gravity at Perimeter in October. They've been posting video of talks like this on PIRSA fairly consistently. So I expect Dowker's talks will be online--a short introductory...

I'm looking for a book that describes Quantum Field Theory from a group theory approach for mathematical physicists (with emphasis on the physics part). Ideally I want it to first describe and define groups, representations and irreducible representations. The more rigorous the math, the better...

Homework Statement \int\sqrt{1+cos^2x}dx The Attempt at a Solution This problem is part of a bigger picture, and I can't seem to figure out how to approach this integral.

So I received an email today about how Mars is supposed to be the closest to Earth in like 5000 years and that it should look like a smaller moon directly next to the normal moon. I looked around the internet and some sites say that its a hoax. Does anyone know anything about this at all?

Homework Statement solve using undetermined coeffecients y"+3y=-48x^2e^(3x) Homework Equations x^2e^3x gives a Yp=(Ax^2+Bx+C)e^3x The Attempt at a Solution I can get yc easily which is yc=cos(sqrt(3x))+sin(sqrt(3x)) However, I'm not sure as to how to set it up so that...

i came across the term kernel approach when reading about a non parametrised unbinned method of analysis. what does this mean? cheers

[b]1. A proton an an alpha-particle are projected with a velocity v=(Ke^2/mL)^0.5 each, when they are far away from each other. If their initial velocity vectors are anti parallel to each other, with a distance "L" between them, find the distance of closest approach.(mass of proton = m, charge...

I think I'm more of a visual learner than the average person because I find books never provide enough pictures so I have to come up with my own mental image to represent the majority of the concepts I come across. An example is right now I'm trying to comprehend the concept of a joule second...

hi, i am interested in nuclear physics but i don't really want to delve into the complexity of it, so could someone please give me an idea of the practical approach to making a breeder reactor, i do not intend to build one, i just would like to know how i would do it if did want to build one...

Hi Why is the lim(h->0) of h = 0? I'm new to this so I'm probably being thrown by the change in variable? Is it because we assume f is a function of h, f(h) = h which we know is continuous from other proofs elsewhere, which gives lim(h->0) f(h) = f(0) lim(h->0) h = 0 thanks

The Schwarzschild solution can be obtained by using Newton for the weak field. However it turns out that this in fact is the exact solution. Is this coincidence or is there more to it? Opinions? http://arxiv.org/pdf/gr-qc/0309072v3

Homework Statement Hi, I am given the following action S: S=1/2∫〖g^ab ((∇_a Ф ∇_b Ф)+(1/6 R_ab Ф^2) ) √(-g) dx^4 〗 Where R_ab is the Ricci tensor, Ф is a scalar field and g^ab is the metric. I am asked to find the equation of motion for the field. Homework Equations I know I...