Coefficient Definition and 1000 Threads

Consider this Ito proces: $$dX_t = \mu(X_t,t)dt+\sigma(X_t,t)dW_t$$ with W_t being a wiener process. My question: What is the diffusion coefficient of X? My motivation for asking: A lot if financial literature refer to "diffusion coefficient" and I haven't understood by googling it, because...

Homework Statement In a particular fibre, the attenuation coefficient for Rayleigh scattering is measured to be 0.30 dB/km at 1.20 μm. (a) How large would it be expected to be at 0.80 μm? (b) Ignoring other sources of attenuation, if a signal of a certain initial power was sent over a...

I was wondering that if rolling resistance is basically caused by slight deformation of a body, we must have formulas in place to relate it to the physical and material properties of a body. But when I went ravaging for it in library or internet, everything was experimental. I wished to know...

Homework Statement Coefficient of xy(z^-2) in (x-2y+3(z^-1))^4 Homework EquationsThe Attempt at a Solution [/B] I was wondering if anyone could give me an explanation for my answer? The coeffecient of xy(z^-2) does not = 4 where I would be able to use the multinomial theorem. So since I...

Hi all, I have a suspended seat with a scissor mechanism like the following: This seat is composed of coil spring and a hydraulic damper. My aim is to develop a multibody model of that seat. Actually, my model is quite complete, only the parameters of damper are missing (i.e. the damping...

I have conducted an experiment that measures the velocity of an object that is moving on a flat surface. The object rolls on four fixed caster wheels. The wheels are made of some kind of rigid material. Maybe nylon, maybe hard rubber. The total mass of the object, including the wheels, is...

I'm having trouble with trying to find the expansion coefficients of a superposition of a Gaussian wave packet. First I'm decomposing a Gaussian wave packet $$\psi(\textbf{r},0) = \frac{1}{(2\pi)^{3/4}\sigma^{3/2}}\text{exp}\left[ -\frac{(\textbf{r} - \textbf{r}_0)^2}{4\sigma^2} + i\textbf{k}_0...

Hey guys, I've got this question, that I think I have figured out, but I'm not completely sure. Basically, I've got the following matrix to put into RREF. Not really a problem, but I'm not sure if I'm handling the variable incorrectly. $\begin{bmatrix} 1 &-1 &|1 \\ 3 &a &|3 \end{bmatrix}$...

Homework Statement Your company needs to install a cold room which will maintain a temperature of -15 degrees operating in a room where the temperature is 20 degrees. A new member of staff has considered the specifications of two manufacturers and asked you to check their figures. Explain what...

Hi! Basically I have some tasks in thermodynamics calculating the heat transfer through a wall. I have been attempting to solve the following problem: “Calculate the heat transfer through the exterior wall in a building, where the temperature inside the building is 20 °C and the temperature...

When I type "drag coefficient" in Google, and view some of the images, the standard list of geometrical shapes come into view, such as this one: https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/14ilf1l.svg/220px-14ilf1l.svg.png If we take the cone for example, there is a drag...

Hi all, Quick question: What do you guys use as your reference for minor head loss coefficients (k). I'm sure those with more experience have their own database/excels of k values found over the years. I have been personally using a combination of my Hydraulic Engineering Textbook and Google...

Hello PF, in Carroll’s “Spacetime and Geometry”, he works out the transformation law for connection coefficients in his introduction to covariant derivatives, and I’m wondering if there is a typo in the final equation. He starts with$$\nabla_{\mu} V^{\nu} = \partial_{\mu} V^{\nu} +...

Hello. I have an equation which I understand partially but after understanding the purpose of coefficients in the below equation I think my understanding will enhance. * I found it on: https://www.desmos.com/calculator/dnzfajfpym What decides that I need coefficients for x2 in the given...

I am working on HFSS and designing Antennas for LOW RCS , in all previous works they calculate the S11 parameter for the unit cell then make an array form this unit cell and calculate the RCS , my question is what is the relation between S11 and RCS and why we calculate S11 for the unit...

Homework Statement The speed of a 4.0-N hockey puck, sliding across a level ice surface, decreases at the rate of 0.61 m/s2. The coefficient of kinetic friction between the puck and ice is: A) 0.062 B) 0.25 C) 0.41 D) 0.62 E) 1.2 Homework Equations I'm not too sure but i know that : If the...

Specifically as to the validity of CoR as a metric for the bounciness of an object. CoR is inherently a property of /two/ objects, say, the interaction between rubber and steel. Is it truly the case that given two objects, it's impossible to say that one object is bouncier than another? This is...

(Oh my god, why can't my post show normally? Some sentences just disappear, but I can still see them while editing. It's very weird. Can someone help me? I've reported.)I know only partially filled bands result in current density, and I think there must be not only 2 partially filled bands, but...

Homework Statement Find roots of $$ -\lambda ^3 +(2+2i)\lambda^2-3i\lambda-(1-i) = 0 $$ Homework EquationsThe Attempt at a Solution I tried my old trick I tried to separating the 4 terms into 2 pairs and try to find a common factor in the form of ##\lambda + z## between them, $$ -\lambda ^2...

Homework Statement Homework EquationsThe Attempt at a Solution Coefficient of volume expansion γ = ∆V/V∆T VT2 = constant Differentiating we get , T2∆V + 2VT∆T = 0 ∆V/V∆T = -2/T So , option 2) looks right . Is that correct ? How do I interpret the answer ? Does that mean the...

Homework Statement A block of mass 20kg is on rest on a rough plane inclined at 60 degrees to the horizontal. A force P is applied to the block to "maintain equilibrium". P is parallel to the line of greatest slope of the inclined plane. The maximum value of P is twice the minimum value of P...

I am extremely confused by the use of the term coefficient of increase of something. For example , if it is stated that the index of refraction varies linearly with a coefficient of 2.5×10^-5, how is this coefficient defined? Is it simply the slope of the line plotted with index of refraction on...

Homework Statement (I) Explain what is meant by an 'overall heat transfer coefficient'. (II) Explain what is meant by fouling and what its effect will be on the value of the overall heat transfer coefficient. 
 Homework Equations None provided. The Attempt at a Solution (I) The overall heat...

Homework Statement I am conducting an experiment where I am interested in finding the absorption coefficient of different materials as muons pass through them. My data was all well until I realized more muons were measured AFTER they passed through one of the materials, which makes no sense...

Hello everyone, I am interested on simulating the converse Piezoelectric effect of materials and I have given the mechanical (Youngs modulus and Poissoin's ratio) and electric material properties (Electric Permittivity, Piezoelectric coupling matrix etc). However from the literature I got...

Homework Statement Ladder leans against wall at angle θ. It is L meters long and mass m. Find the coefficient of friction with the floor. Assume no friction at the top.[/B]Homework Equations ΣFx = 0 ΣFy = 0 Στ = 0 ƒ = μFn (Fn being the normal force with the ground) The Attempt at a Solution...

Hi, When considering the drag coefficient of a rocket in transonic/supersonic flight, I always expected the drag coefficient to peak at exactly Mach 1 due to the abrupt increase in pressure that occurs when breaking the sound barrier. However, I have been looking at several websites and...

Homework Statement So, the question is based around an experiment to determine the coefficient of viscosity for water (by capillary flow). Part of the experiment involved producing a graph of Q against h. This graph is supposed to be linear, and is supposed to pass through the origin. As can be...

Homework Statement I need to find the coefficient of kinetic friction from a set a lab data that I found. I had a mass connected to a mass hanger by a pulley, and measured the acceleration of the mass with various amounts of mass on the hanger. In the attached image, the acceleration was...

Homework Statement A 5.0kg block of wood sits on a table with a string running over a pulley suspending a mass. The largest mass that can be suspended without moving the block of wood is 0.75kg. a) Calculate the coefficient of friction in this case. b) What type of coefficient of friction has...

Homework Statement How can I estimate the decay coefficient in Ae^-at for this graph I know the equilibrium position Homework Equations damped oscillation The Attempt at a Solution not sure if this is right.[/B]

Hi there, So I asked a question here how I would calculate the air drag and the wheel drag of a train and I got an answer that made me very happy. Unfortunately i don't know where i could find the coefficient values required for the formulas. So i am wondering if someone knows where i can find...

Hello everyone, I don't seem to understand why mass Attenuation coefficient is greater than 1 at low energies where photoelectric effect is dominant. 5.2 cm^2 /g at water for 10 kev incident photons. Since it is the probability to interact per g of water how can it be greater than 1? I...

Hi guys, Yesterday I sat down, and just for fun, decided to calculate the coefficient of kinetic friction for the all electric Ford Focus. I keep getting the wrong answer, and it is driving me crazy. Here are the facts. Battery: 23 kWh. Curb weight: 1,651 kg. Maximum travel distance before a...

Is linear attenuation coefficient a constant for a given material or will it depend on the thickness of the material?

Hello, For calculating the mean power at a specific cross section of a waveguide, one can calculate the mean value of the temporal function of Poynting Vector, P(t), where P(t) is the ExHy-EyHx. Note that I am not talking about phasors or a sinusoidal state. If I integrate over the waveguide...

Where does the Coefficient of Restitution equation come from, in terms of the Conservation of Energy? The measure of efficiency is the velocity after the collision divided by the velocity before the collision, but how does it get to that point? I'm trying to view this focused on an object that...

Hi, I am looking into aerodynamic parameters for rockets (ogive nose, cylindrical body of different diameters, four fins at bottom) and have a question about the lift coefficient. If a rocket is launched vertically, with zero incidence angle and wind, would that result in a very small lift...

I am comparing three brands of tires to see which one provides the lowest rolling resistance and thus give the best efficiency at low speeds. I have the information of the tires such as footprint, weight (of the tire and load), speed. How would i go about doing this ? am really stumped thanks

<< Mentor Note -- Two threads on the same subject have been merged >> I am a junior enrolled in IB Physics at the standard level at my high school. As a part of the curriculum we must perform an Internal Assessment (IA) which involves performing an experiment and performing calculations and it...

Hi PF! Generally speaking, how would one solve $$f''-a(x) f = 0 : f(0)=0,f'(0)=1$$ Or if you could point me to a source that would be awesome too!

Homework Statement Determine the coefficient of friction for a surface when the mass of an object is 300g and the angle of incline when the object starts to move is 29° Distance traveled and acceleration are not provided Homework Equations W = mg Ffric = μN N = mg cos(θ) μN = mg sin(θ) The...

Homework Statement Hello, I have a general question regarding to coefficient matching when spanning some function, say , f(x) as a linear combination of some other basis functions belonging to real Hilbert space. Homework Equations - Knowledge of power series, polynomials, Legenedre...

Homework Statement I have data for the count rate (of gamma rays) against the thickness of various materials (Al, Pb, Fe etc...). I want to work out the linear attenuation coefficient. Can I do this by plotting the natural log of count rate against thickness? I don't have values for...

Homework Statement Homework Equations W = Fk d cos θ Fk = FN μκ The Attempt at a Solution Here's my work : m = 1 kg vi = 10 m/s vf = 0 m/s xi = 0 m xf = 0.1 m d = 0.1 m k=60 N/m μκ=? The work done be the frictional force : W = Fκ d cos θ = FN*μκ*d*cosθ = mg μκ d cos 180 =...

Homework Statement Homework Equations W = ΔUg + ΔkE + ΔUs KE = 0.5 m v^2 Ug = m g h Us = 0.5 k x^2 The Attempt at a Solution k = 60 N/m vi=0 m/s (" the block is released from rest ") xi= 0 m/s ( "the spring is unstreached") vf= 0 m/s xf= 0.2 * sin 37 = 0.2*0.6 = 0.12 m d= 0.2 m...

I'm new to the forum and after some help if anyone can explain. I've read a few articles now, which have stated that the average co-efficient of friction for a tire with tread will be between 0.4 in the wet and 0.7 in the dry. If instead the tire had no tread, the co-efficient of friction will...

Im a high school student and am in AP Physics 1. I just created a formula for calculating the coefficient of kinetic/static friction between two objects using only distance and time (I don't have a way to measure Newtons). Is it correct and can it be used in the real world?

Homework Statement A coffee cup in your dashboard slides forward when you decelerate from 20 m/s to rest in 3.5 s or less, but now if you decelerate for a longer time. What is the coefficient of static friction between your coffee cup and your dashboard? Homework Equations a = delta a / delta...

So I did a project about a year ago and I can't remember one of the things I wrote in this equation. The equation apparently I got it from NASA's website. https://www.grc.nasa.gov/www/k-12/airplane/dragco.html This is my equation CD = FL/ (0.5 * Air viscosity * V^2 * Area) = 0.4These are the...