Section Definition and 733 Threads

This isn't a homework problem. I am preparing for a particle physics exam and although I understand the theoretical side of field theory, I have little idea how to approach practical scattering questions like these. THE PROBLEM: Dark matter might be observed at the LHC with monojet and...

Stuff I'm wondering about: * can/does a conductors' cross-section influence inductive efficiency and/or directionality? * consider a 'wire' made from a dielectric material, with a conductive material evaporatively deposited on it's surface. if this wire were asymmetrical in section, e.g. it...

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Hi, I'm planning to build a climbing wall outside my house, attached to a concrete wall. The climbing wall would be 3 sheets of 18mm plywood (each about 30kgs) - each 2.5m x 1.22m (8ft x 4ft). With the boards set out 2.5m wide and stacked 3 high to give a max height of 3.66m (12ft). I want the...

Homework Statement I do not understand how the authors got the time derivative of equation 1.5-4 in the form given at 2.5-2. Homework Equations The Attempt at a Solution \frac{d}{dt}\frac{p}{1+e...

...based on the angle. Homework Statement Figure 30-78 shows a wire that has been bent into a circular arc of radius r = 24.0 cm, centered at O. A straight wire OP can be rotated about O and makes sliding contact with the arc at P. Another straight wire OQ completes the conducting...

Hello. I'm trying to calculate the total collisional cross section of the hydrogen atom impacted with the proton. (ion of the hydrogen plasma) I've found many good papers but they're showing specific cross section, for example, total cross section when n = 1 state is direct-excited to n =...

Homework Statement Two blocks of masses M and m are oriented as shown in the diagram. The block M moves on a surface with coefficient of kinetic friction μ_1, and the coefficient of static friction between two blocks is μ_2. What is the minimum force F which must be applied to M such that m...

Homework Statement What is the cross section if the density of atoms in a material is 10^26 metres-3, and 0.04% of a beam of neutrons is stopped in a 2 cm slab of the material ? Homework Equations Sigma = event rate per nuclei / incident flux The Attempt at a Solution I have...

Imagine having a road that's going straight forward, where each section is 1/10 the size of the last section. The sections would be blue, then red, then blue and so on. Assuming the size of the first section is one meter, the road would be 1.111... meters repeating. Each time you drive...

I have a question regarding the calculation of the cross section in muon pair production from electron positron annihilation. After some calculations the textbook comes to the conclusion that the differential cross section is approximately equal to: (1+cos(theta)^2)alpha^2/(4*s) where alpha...

Homework Statement The question asks for resistance R of a disk with radius r and fixed width w, whose cross sectional area is variable. Unlike in the picture below, the resistor is not connected to the circuit on the flat ends, but on the cylindrical sides. Homework Equations...

How do I calculate radar cross section given the diameter of a spherical object and the radar's frequency in GHz? Thanks

Find the radius of the circular section of the sphere of the sphere x^2 + y^2 + z^2 = 49 by the plane 2x+3y-z-5 \sqrt{14}= 0

I'm trying to find specific reaction cross section 18O(p,n)18F in proton + O-18 TENDL (ENDF format). # p + 18O : (p,n) Total # Q-value =-2.51902E+00 # E-threshold= 3.64964E+00 # # energies = 45 # E xs 1.000E+00 0.00000E+00...

http://en.wikipedia.org/wiki/Gamma_matrices#Normalization See the image below. Which of us is right: me or Wikipedia?

I am reading Paolo Aluffi's book, Algebra: Chapter 0. I am studying Chapter II: Groups, first encounter. In Section 3 of this chapter, Aluffi deals with the category Grp in which the objects are groups and the morphisms are group homomorphisms. Section 3,3, which is a pause for reflection...

A long piece of sheet metal w inches wide is to be bent into a SYMMETRIC form with three straight sides to make a rain gutter. A cross section is shown below. \_____/ The base is w-2x and the angled side lengths are both x with a theta between top horizontal. A. Determine dimensions that...

I am reading Paolo Aluffi's book, Algebra: Chapter 0. I am, at present, focused on Chapter 1, Section 5: Universal Properties. I subsection 5.3 on Quotients, Aluffi writes the following: I am uncertain of the nature of the category that Aluffi is constructing. in particular, do the functions...

In terms of unit material spent my impression is that an I beam uses it most efficiently at least for non-torsional loads? i.e. putting most material far from the axis into the flanges giving higher moments. If so, what are situations when an angle or channel cross sections are preferred in...

I've got a 300 liter water heater that has an electrical element (14 kW). The issue is that the element is positioned in the top third of the heater. I fear the water will become segregated so that only water in the top third will be heated, and the lower section will remain cold. The target...

So I'm working On hydrostatic pressure. The problem #8 in stewart Is a trapezoid with the base above water. 4 \------------------------/ 1(above watee) \ / 1(in watee) \ / --------------- 2 So if the...

As we know RCS is measure of how detectable an object is with a radar. But I don't understand one thing. If we take a sphere as an example, we can see that RCS is the largest in forward direction (forward scattering). If the sphere is to big (radius>>lambda), still this forward scattering is...

I am reading Dummit and Foote, CH 10 Section 10.5, Exact Sequences - Projective, Injective and Flat Modules. As they introduce split sequences, D&F write the following: I am concerned at the following statement: "In this case the module B contains a sub-module C' isomorphic to C (namely C'...

I have this problem in my review packet and it is making me crazy because it wasn't covered in lecture and the book seems to just skip over it. The final is tomorrow and I don't really have a clue about phase relationship between current and voltage in a simple ac circuit and filtering...

What are three different ways that i can produce a hole with a square cross section in a plate with a thickness of at least 1"?

Hi, I'm doing a project to see the feasibility of transmuting tungsten into platinum on a small scale (maximum output of 1 kg per month). However, some of the cross section data that I need seems to be hard to find. Now because I am new to this, I don't know if its because no body has...

Hi all, I think that the off shell decay dosn't decrease the decay cross section, I mean if a particle X decays into a jet pair has mass for example Mjj ~ 130 GeV, being X has mass M ~ 130 GeV so decay in resonance or on shell into jj or being MX even much greater ~ 2000 GeV , this...

Hi all I was trying to understand the Born-Bethe approximation related to cross sections for atomic and molecular collisions. All the stuffs that i got are explaining in complicated way which am not able to follow. Can anyone explain in simple terms what the theory explains? It will be of...

Homework Statement Find the flux of F=<y,-x,z> through the piece of ρ=2 that lies above z=1 and is oriented up. Homework Equations The Attempt at a Solution S = < x, y, \sqrt{4-x^{2}-y^{2}} > Take Find Sx and Sy, cross them and end up with: dS = <...

Homework Statement Using the Eikonal approximation (1) Determine the expression for the total scattering cross section of a particle in a potential V(r) (2) Using this result, compute the total scattered cross section for the following potential. V(r)= \begin{cases} V_0, \text{for } r < a \\...

What does "cross section area" mean when dealing with stress/strain? Homework Statement For clarification, here is an example problem: A circular steel wire 2 m long must stretch no more than 0.25 cm when a tensile force of 400 N is applied to each end of the wire. What minimum diameter is...

Hi, I am self-teaching Quantum Elctrodynamics, and have come across something which I do not understand. I would appreciate feedback from anyone on this specific issue from Atchison & Hey, "Guage Theories in Particle Physics" pg 238-239: In calculating the u-channel electron-muon...

I am reading Dummit and Foote Section 10.5 Exact Sequences - Projective, Injective and Flat Modules. I need some help in understanding D&F's proof of Proposition 27, Section 10.5, page 386 (see attachment). Proposition 27 reads as follows: (see attachment)...

Homework Statement For a laser, assume single mode operation, only lifetime broadening due to A21 and A1. Write out the rate equations for the atomic densitions N1 and N2 and the flux \Phi. Then there's a diagram where there's 2 stats. Pump rate is P, stimulated emission between 1 and 2 is...

Homework Statement I've been reading through Quantum Optics by Scully and Zubairy and have been stuck in section 6.2 getting from the definition of the atomic inversion given by equation (6.2.20, pg 199) W(t)=\sum_{n}\left[|c_{a,n}(t)|^2-|c_{b,n}(t)|^2\right] to the atomic inversion for the...

I am reading Dummit and Foote Section 10.4: Tensor Products of Modules. I would appreciate some help in understanding Example (8) on page 366 concerning viewing the quotient ring R/I as an (R/I, R) -bimodule. Example (8) D&F page 370 reads as follows: (see attachment)...

I am reading Dummit and Foote Section 10.4: Tensor Products of Modules. I am currently studying Example 2, page 363 (see attachment) and I am trying to closely relate the example to Theorem 8 and the D&F text on extension of the scalars preceding Theorem 8 on pages 359-362) In Example 2 (see...

I am reading Dummit and Foote, Section 10.4: Tensor Products of Modules. I am studying Corollary 9 and attempting to fully understand the Corollary and it proof. (For details see the attachement page 362 in which Theorem 8 is stated and proved. This is followed by the statement and proof of...

I am reading Dummit and Foote, Section 10 on tensor products of modules. I am at present trying to understand the use of Theorem 6 (D&F, page 354 - see attachment) in Theorem 8 (D&F page 362, see attachment). The proof of Theorem 8 in D&F Chapter 10 (see attachment) reads as follows...

In Dummit and Foote, Section 10.4: Tensor Products of Modules, on pages 359 - 364 (see attachment) the authors deal with a process of 'extension of scalars' of a module, whereby we construct a left S-module S \oplus_R N from an R-module N. In this construction the unital ring R is a subring of...

Dear Forum ： I'm looking for proton-proton inelastic cross section in MeV. There are lots of results in GeV, TeV. But I can not find the results in MeV in ENDF nor TENDL. https://www-nds.iaea.org/exfor/endf.htm ftp://ftp.nrg.eu/pub/www/talys/tendl2011/proton_html/proton.html Please advise...

I am reading Dummit and Foote, Section 15.4 Localization. Exercise 12 on page 727 reads as follows: ------------------------------------------------------------------------------- Let R = \mathbb{R}[x,y,z]/(xy - z^2) , let P be the prime ideal P = (\overline{x}, \overline{y}) generated by...

Homework Statement See the problem attached in this post. Homework Equations See the problem attached in this post. The Attempt at a Solution I set my limits of integration with respect to z axis and got an upper limit of 2 since that's the vertex point/height of the pyramid...

I am reading Dummit and Foote, Example 2 of Section 15.4, page 708. Rewriting the assertions of the example as exercise style questions, EXAMPLE 2, reads as follows: ------------------------------------------------------------------------------------- Let R be any commutative ring with 1 and...

Homework Statement The problem concerns the collision of a particle on a rigid, fixed disk of radius R. The coefficient of friction is zero, and the coefficient of restitution is 0 < ε < 1, such that vperpendicular, final = εvperpendicular, initial . A) Show that tanαincident = εtanαfinal...

Hi, I've looked under the mathematics textbook section on this site and I can see algebra and geometry but not a single trigonometry book... Is trigonometry normally covered in algebra books something? My trigonometry is really quite terrible and I know the absolute basics so I'm looking for...

Dear Forum: I would like to know where could I find charged particle interaction cross section for oxygen-18? I know I can get some of it from ENDF. https://www-nds.iaea.org/exfor/endf.htm Where can I get reference,like the threshold energy for 18O(p,n)18F is 2.5MeV and its cross...

Homework Statement I want to know the section modulus for a beam which has a UDL of 13.5 kn/m across 10 metres. Its simply supported at both ends. max allowable stress = 255 MPa Homework Equations Z= M / max allowable stress [cm^3] The Attempt at a Solution max bending...

Homework Statement Homework Equations The Attempt at a Solution Hello, Comparing these two problems, 9.6 says to calculate the elastic curve for portion BC. However, in the solution they include the contribution from P which is not contained in portion BC in the representative cut to calculate...