Parameter Definition and 352 Threads

I'm trying to understand a few things about the kinematics of collision processes. I guess it's because we calculate the scattered angle of the projectile and then back calculate to get a value for the impact parameter. Is this right?

Homework Statement A proton of mass m, charge +e and (asymptotic) momentum mv is incident on a Nucleus of charge +Ze at an impact parameter b. Consider only coulomb repulsion and classical mechanics, what is distance of closest approach - d? Homework Equations Haven't encountered impact...

I must have a mental block here! Given r(t) = (x(t), y(t)) = (-3t, 4t) - clearly this passes through the origin. Eliminating t results in $4x + 3y = 0 $. Normalising gives $\frac{4}{5}x + \frac{3}{5}y = 0 $ which we can write as $ \vec{n}.\vec{r}=0 $ , i.e. $ \vec{n} = \left(\frac{4}{5}...

Hi, I'm having trouble answering Question 9.20 in Hobson's book (Link: http://tinyurl.com/pjsymtd). This asks to prove that a photon will just graze the surface of a massive sphere if the impact parameter is b = r(\frac{r}{r-2\mu})^\frac{1}{2} So far I have used the geodeisic equations...

I would like to know a typical W/L value for a MOSFET transistor. L = channel length W = channel width/transistor width I am currently designing L to be L = 0.0001 cm for a transistor. Cox = 5nF mobility 1155 cm^2/Vs K = 0.583 mA/V^2 This gives W = 20 cm. But this is way to large for a...

Homework Statement A pendulum with a mass of 0.1 kg was released. The string made an angle of 7 ° with the vertical. The bob of the pendulum returns to its lowest point every 0.1 seconds. What is the period, frequency? Homework Equations T= 1/f T=sec/cycles F= cycles/sec The Attempt at a...

Homework Statement Find the arclength parameter s=s(t) for the path x(t)=e^(at)cos(bt)i + e^(at)sin(bt)j + e^(at)k Homework Equations s(t)=\int_{a}^{t}\left | \mathbf{x}(\tau ) \right |d\tau The Attempt at a Solution I took the derivative and squared it, arriving at the equation (-be\sin...

I've come across two different approaches to quantifying what l is in the equation for hydraulic gradient Δh/L. In this first picture L is the parallel distance along the datum across the reference plane But in this second picture L is the length along the pipe Why are the two L's...

Hi, I have to solve one equation on Matlab. The equation is: (p-c)*psi'-psi=0 I have to find p. Where psi is: and psi' is the derivative of psi. I've written this code: rho = 0.04; %In the image is lambda c = 25; eta = 0.02; mu = 40; sigma = 0.57; alpha = -rho/eta; syms p t F =...

I am having some issues with this problem I am doing. I will show what I have done so far and where I am getting confused. 1. Homework Statement The 2-port shown in Figure 2 is characterized by its Z-parameters, where ##Z_{11}=Z_{12}=Z_{21}=Z_{22}=R##. Find the input impedance ##Z_{in}##...

Is the multiverse universe so vast that everything has or will happen?

https://en.wikipedia.org/wiki/Immirzi_parameter Quote:The Immirzi parameter seems to be the only free parameter of vacuum LQG Hence LQG should provide formulas (or numerical calculation) for all dimensionless parameters of standard model . For now, at least the raw idea, where they come from...

Another paper in Friday's physics arXiv on using the H(z) v z plot to investigate any possible evolution of DE: Utility of observational Hubble parameter data on dark energy evolution. From that eprint: As discussed in the Marginal evidence for cosmic acceleration from Type Ia SNe, this paper...

At first, we need some state parameters(like P/T/V) to fully describe a system. And the order parameter is also a parameter which could describe the property of the system. However, in the Laudau theory, why it said that order parameter is an external parameter(not a independent variable)? Is...

Hello, I am attempting to eliminate the parameter from r'(θ) = r'(θ)=<-10sinθ,10cosθ> , but when I do, I get back to the same equation as I would for eliminating the parameter for r(θ)=<10cosθ,10sinθ> (1) x^2 + y^2 = 10 y = \sqrt{10-x^2} (2) y' = \frac{-x}{\sqrt{10-x^2}} then, since x^2...

Mod note: I revised the code below slightly, changing the loop control variable i to either j or k. The reason for this is that the browser mistakes the letter i in brackets for the BBCode italics tag, which causes some array expressions to partially disappear. Hello, I am trying for the first...

...r than 1? This is the slide we have been given in class So what on Earth would the structure of PA, PC and PE be? I understand the closer to 1 it would be a bilayer so PC is likey a bilayer but can't understand what the others would be from this slide, does anyone have any ideas?

I am trying to solve a large least squares inversion (inverting data for the modeled sources), and find that my parameters describing 1 source are highly correlated with the parameters describing the second source. Can anyone recommend a technique or reference which discusses how to reduce the...

x = 2 − π cos t y = 2t − π sin t −π ≤ t < π I understand how to eliminate parameter using sin^2 + cos^2 = 1. I can't figure out how to deal with the "2t" in the y equation, if you solve for sin(t) and square, you get ((2t-y)/π )^2 which leaves the parameter. Is there a way to get it into the...

I have \begin{figure}[h] ... \end{figure}, but it's just placing the figure at the top of the page. do i need some package? which one? thanks very much.

For the distance function ##(\Delta s)^2 = (\Delta r)^2 + (r \Delta \theta)^2##, the rotation matrix is ##R(\theta) = \begin{pmatrix} cos\ \theta & - sin\ \theta \\ sin\ \theta & cos\ \theta \end{pmatrix}##. That means that for the distance function ##(\Delta s)^2 = (\Delta r)^2 +...

If ##\sigma## is an affine paramter, then the only freedom of choice we have to specify another affine parameter is ##a\sigma+b##, a,b constants. [1] For the tangent vector, ##\xi^{a}=dx^{a}/du##, along some curve parameterized by ##u## My book says that ' if ##\xi^{a}\xi_{a}\neq 0##, then by...

Hi all, I am trying to obtain an empirical equation/model having 2 inputs (frequency and S11) and one output (a physical parameter) I have done various simulations using CST of the System and now I am trying to relate S11 and frequency to a physical parameter. Any suggestions of how I should go...

Homework Statement Find the speed parameter β and Lorentz factor γ for an electron that has a kinetic energy of: a) 6.00 keV b) 2.00 MeV c) 4.00 GeV Homework Equations KE=(γ-1)*511 KeV SQRT(1/(1-β^2))=γ The Attempt at a Solution a) 6 KeV=(y-1)*511 y=1.0117 1.0117=SQRT(1/(1-β^2)) β=0.152 b)...

Dealing with CMB, people sometimes refer to the shift parameter; R = \sqrt{\frac{\Omega^0_m}{\Omega^0_k}}sinh(\sqrt{\Omega^0_k}\int^{z_{dec}}_{0}{\frac{dz}{E(z)}}) I know that it is related to the position of the first acoustic peak, however, the amount is around 1.7. What does this mean?! does...

I have a question about the logistic fit they used on this paper: http://online.liebertpub.com/doi/pdf/10.1089/cmb.2005.12.1047. Its PDF page 5, or journal page 1051. They define all the variables and then say x0 and b define the shape of the model. If I am fitting 30 cycles of PCR data how am I...

This is probably a stupid question but does k=1,0,-1 correspond to closed,flat,open refer to space or space-times? Looking at a derivation what each geometrically represents is only done when talking about the spatial part of the FRW metric. As space can be flat and space-time still curved...

Hi everyone! I am trying to find the parameters of a surface mounted PM synchronous motor using the application note AN4680 (PMSM Electrical Parameters Measurement) and had some queries regarding it. The Ld process is mentioned as follows 1. Align the rotor to phase A. Phase A is connected to...

Homework Statement 2-1. A constant torque of 4 Nm is applied to an unloaded motor at rest at time t = 0. The motor reaches a speed of 1717 rpm in 4 s. Assuming the damping to be negligible, calculate the motor inertia in Nm·s2. Homework Equations T = J(eff) * dw/dt J = kg*M^2 The Attempt at a...

A line in 2-dimensional euclidean space can be determined by the coordinates of any two particular points on the line. Hence four "parameters" are required. Now let’s consider a line given by the usual equation y = mx + c. c, being the intercept on the y-axis, is related to the point (0,c) which...

I've understood that the main evidence for a non-zero ##\Omega_\Lambda## comes from supernova 1a measurements where one measures the redshifts along with the luminosity distances (equivalently magnitude) of the supernovae and, plots them against each other, then compares the result with...

For those of you who know what a Hansen Solubility Parameter is, does the "hydrogen-bonding" part means the actual hydrogen bond energy between molecules? I'm confused as to why they used mPa^0.5 instead of kJ/mol^-1 for measurement.

Hi, suppose that you have some function: F(x;a) where x is the variable with which you plot the function and a is some parameter which enters the function. If I want to find the error coming from some uncertainty in a, computationally, I would have to plot the function for 2 different let's say...

As I know each function can have no parameter this function is called void function ,for example main function, also there is some functions which has one or more parameters either input or output , the number of parameters should be specified in the function prototype and function definition...

Homework Statement hi. i have a linear equation with parameters that i am trying to solve. unknowns are x, y and z. (12-3t)x + 2y +2z =2 x +0*y +2z =0 12x + (2-t)y + (2-t)z = 12 i am using a matrix-approach with Gaussian-elimination, and my results (for values of t which allows for a...

how to prove Any curve in space can be written as for a parameter

Hello Community! I can't find a good answer(if there is) to my question. When in statistical mechanics we can define the order parameter for to study some phase transition. we need to define a order parameter. Now, I want to know if we can to define/find some "order parameter" for to...

I'm looking at general relativity and particularly considering what happens at the Big Bang. I think the Friedman equation is H^2=\frac{8\pi G}{3}\rho so I see that as the matter density goes to infinity, H goes to infinity. According to this video (around 10:10), this is where the problem lies...

While I am studying the wave propagation in fluids, the amplitude modulation seems to be governed by the Nonlinear Schrodinger (NLS) equation. In some of the journal papers the nonlinearity parameter, N seems to be of high value (N≈O(104)) and so on. I understand that weak nonlinearity...

Is rather a question of calculus skills, but how do I get the time derivative of the Hubble parameter here in [1]? Is it the Leibnitz rule, the chain rule, some clever re-arrangement? thank you

Hello to everyone, I got a little bit confused between the coupling constant g_W and the strength parameter \alpha_W in the weak interaction. For what I know they should both give an idea of the strength of the interaction but I miss to understand what's the difference between them.

Homework Statement For the negative binomial distribution, with r known, describe the natural parameter space Homework Equations the pmf for the negative binomial distribution with parameters r and p can be 1) P(X=x|r,p)= \binom {x-1}{r-1}p^{r}(1-p)^{x-r} where x=r,r+1,... , or 2)...

Hey! I'm doing a lab assignment and need some guidance. i have measurement with L=1μmeter and w=10μmeter, but the id data is normalized to w=1μmeter, what does it mean? do I need to get Ids "un-normalized" for extraction, like Ids*1e-6= new Ids the second question is about low-field...

Homework Statement Give q(t) the deceleration parameter, as a function of: \Omega_{\Lambda}, the cosmological constant density, and \bar{a}(t) = \frac{a(t)}{a(t_{0})}= 1+ H_{0} (t-t_{0}) - \frac{1}{2} q_{0} H_{0}^{2} (t-t_{0})^{2} where a's the scale factors have already defined τ =...

Homework Statement For what values of a, from the reals, does the limit exist? lim_{x\rightarrow2} (\frac{1}{2-x}-\frac{a}{4-x^{2}}) Homework Equations I chose a so that the denominator would be one. By putting the fractions together. The Attempt at a Solution When a = 4 the...

Hey guys, I'm reading the Theory of Sound and I've come to a part in which I'm having trouble double-checking the algebra. Suppose we have two harmonic sound waves of equal amplitude traveling directly perpendicular to each other. \begin{align} u=acos(2πnt-ε) && v=bcos(2πnt) \end{align} They...

Hi everyone, I have what may be a dummy question. In NMR or in the study of liquid crystals for example, an order parameter S is often used: S=\left\langle\frac{1}{2}\left(3\cos^{2}\theta-1\right)\right\rangle with \theta the angle of the molecule with a "director" (the magnetic field in...

Homework Statement Determine for what value/s of the parameter a the following planes in R3 are perpendicular: ax + 0y - 5z = 3 ax + ay + 5z = -26 Write answer in form {a,b} or {a} Homework Equations I know that in R2 two vectors are perpendicular if u*v = 0 What what do I use for...

Homework Statement I have the functionu(x,t)=\frac{1}{2c}\int^{x+ct}_{x-ct}g(\xi)d\xiwhere g is continuously differentiable and c is a constant. I need to verify that this is a solution to the wave equation. Homework Equations My prof gave me the...

1. The problem statement, all variables and given/known If C is a smooth curve given by r(s)= x(s)i + y(s)j + z(s)k Where s is the arc length parameter. Then ||r'(s)|| = 1. My professor has stated that this is true for all cases the magnitude of r'(s) will always equal 1. But he wants me...