Coefficient Definition and 1000 Threads

Hello Physics Forums I’m doing some numerical studies on diffusion. I began with monte carlo simulations on gas diffusion, and more recently I’ve started to dabble in carrier diffusion inside semiconductors. It looks like diffusion in semiconductors is a lot more amenable to experimental study...

What is relationship between discharge coefficient and minor loss coefficient. Am I right with that equations? hl – minor head loss k – minor loss coefficient ρ – air density A – pipe cross section area Cd – discharge coefficient Δp – pressure drop u – air velocity m – mass flow here is...

Hi all, in several vehicles, I measured the engine torque and speed and the engaged gear while it was driven for around 100km/h. I computed the average engine speed and torque of all the times the vehicle was run with each gear and also I computed the relative frequency of the gear used. So for...

1. The problem: A hockey puck is hit on a frozen lake and starts moving with a speed of 11.6 m/s. Five seconds later, its speed is 7.4 m/s. What is its average acceleration? The acceleration of gravity is 9.8 m/s. Answer in units of m/s. What is the average value of the coefficient of kinetic...

< Mentor Note -- thread moved to HH from the technical math forums, so no HH Template is shown > Hello. I'm currently working my way through Lang's Basic Mathematics and cannot make sense of this question: Show that if n is a positive integer at most equal to m, then {m \choose n}+{m\choose...

Homework Statement The coefficient of the term (x−π)2 in the Taylor expansion for f(x)=cos(x) about x=π is: Homework Equations ##cos(x) = 1 - \frac{x^2}{2!} + \frac{x^4}{4!} - \frac{x^6}{6!} + \frac{x^8}{8!}...## The Attempt at a Solution Unless my taylor series for cosine is incorrect, I'm...

Hello Physicsforums! I've stumbeld on a problem in statistics (which is one of my weaknesses when it comes to math). I´m currently trying to analyze data from a study and using multiple regression analysis. From regression analysis with one independent variable I´m used to mainly focus on the...

Homework Statement Homework Equations Cf=0.0577(μ/xρUm)0.2 The Attempt at a Solution I've managed to do parts a) and b), however I don't believe my attempt at the first part is correct as I am using a different Cf than the value used in the mark scheme. The expression I made for the first...

Homework Statement Let ##\prod_{n=0}^{1996} (1 + nx^{3^n}) = 1 + a_1 x^{k_1} + a_2 x^{k_2} + ... + a_m x^{k^m} ## , where ##a_1, a_2, ..., a_m ## are nonzero and ##k_1 < k_2 < ... < k_m ##. Find ##a_{1996}##. From Art and Craft of Problem Solving, originally from Turkey, 1996 Homework Equations...

Homework Statement The equation is z= e (x*y), the interesting thing is y is function of x too, y = ψ(x) Calculate the partial derivative respect to x, and the total derivative. Homework Equations Total differential: dz= ∂z/∂x dx + ∂z/∂y dy The Attempt at a Solution [/B] Well, according...

Homework Statement A small block is on the point of slipping down a rough ramp inclined at 35 degrees to the horizontal. a) What is the coefficient of static friction between the block and the ramp? Answer μ_s = 0.70 b) The ramp is attached to the edge of a 0.8 m high table. After the block is...

Sorry if this is trivial - I'm arguing with someone on Facebook :sorry: who is claiming that r-squared values, or correlation coefficients represents "chance" or "probability". I've never heard of this. I just need a simple yes or no answer along with a short explanation why it is or isn't...

Homework Statement I think I am being stupid, I am trying to show that ## \int^{T}_{0} e^i\frac{2\pi(n-m)t}{T} dt = 0 ## [1] if ## n \neq m## ## = T ## if ##n=m##, ##T## the period. Homework Equations [/B] I am using the following ##cos## and ##sin## orthogonal...

Homework Statement In a lab assignment we created a Fletcher's trolley system and were asked to calculate the normal force, the force of friction, and then create a graph of both to find the coefficient of kinetic friction. So far, the variables I have are: Hanging mass: 0.100 kg Sliding...

Hello! I am a university student working on a project regarding a piezoelectric patch transducer, and RLC modelling of said transducer. Edit: After reading the rule post i think i should clarify this is not coursework homework, this is a thesis project. The short version of my question is how...

I know that the variation in a gas' volume is equal to ΔV = γ⋅V[initial]⋅ΔΘ with ΔΘ the variation in temperature and γ=1/237 the thermal coefficient of expansion in gases. Could someone please explain to me why γ=1/237 please ? Thanks a lot, V

I am building a business cycle index, which include 4 variables that drive the index. Each variable I also include autoregessive coefficients that are all significant and negative. I was wondering what is the significance of this? In other words, what is the significance of have autoregessive...

I have a cuboid shaped box. It is being used as a chilling tank in my refrigeration system based on Evan Perkins cycle. For heat load calculation I tried to calculate the heat leakage in the sysyem. So I considered conduction and natural convection. I am in preliminary stage, so no use of...

Say I have a line of steam with temperature 800 deg C, at 10bars connected with it is a partially evacuated tank 0.01 bar pressure, room temperature. The connection was built with a long capillary and a valve. Does throttling effect experience when the valve suddenly opened? Why and why not?

Homework Statement If the incline of the driveway is 19 ∘ from the horizontal, what must the minimum coefficient of static friction be between your shoes and the ice? Homework Equations Fs=uN The Attempt at a Solution

EXPERIMENT ABSORPTION OF γ - RADIATION IN LEAD AND CALCULATION OF ABSORPTION COEFFICIENT µ Using equation (3) / slope of graph lnC vs d - estimate µ. This should be in units of per meter (m-1 ). The formula in the analysis are as follows : 1. I = I0 e-μd 2. C(d) = C0 e-μd 3. lnC = lnC0...

Homework Statement The coefficient of static and kinetic friction is constant for a specific surface. On an incline plane s and k are both equal to tan of the inclined angle. If the angle increases then tan changes which means the coefficient of friction changes. How is this so? Homework...

Homework Statement A child slides down a slide with a 28° incline, and at the bottom her speed is precisely half what it would have been if the slide had been friction-less. Calculate the coefficient of kinetic friction between the slide and the child. Knowns: 28° speed=V/2 Homework Equations...

xy'' + 2xy' - y = 0 Honestly no clue where to start, Wolfram Alpha gives a rather complex answer lol (http://www.wolframalpha.com/input/?i=xy%27%27%2B2xy%27-y%3D0)

Homework Statement Here is the transfer function of a buck converter I derived: What I need to do next is obtain equations for w0 and ζ. I know how to do this for equations that follow the general form: But in this case I just can't figure out exactly how to do it. How do I find a...

Homework Statement "A rope is used to pull a ##\frac{357}{100}kg## block at constant speed ##\frac{203}{50}m## across a horizontal floor. The force on the block from the rope is ##\frac{768}{100}N## and directed ##15°## above the horizontal. What are (a) the work done by the rope's force, (b)...

Guys,, please check my own way to get Drag coefficient and Terminal Velocity by given Drag force,.. okay,, lets for example: we know drag force is Fd= Cd*pf*v^2*A/2,, ill give little example (Cd=.02)*(pf=1027kg/m^3)*(v^2=.0025m/s)*(A=24m)/2 =( Fd .6162N) so drag force is .6162N,, okay..according...

Hello everyone, I am trying to design an element that its purpose is providing stiffness and damping. The material that I wish to use is rubber. My question is, how can we calculate the damping coefficient (c) for the calculation of the term c*dx/dt, when we know the loss factor of the...

Hello all I'm trying to calculate a torque needed to tighten a threaded terminal. (Both male and female parts are copper alloy) I'm using Motosh's equation which requires me to use the coefficient of friction. Web sources tells me that the copper-copper coefficient of friction is 1.0. The...

1. Homework Statement A block of mass 1.60 kg is connected to a spring of spring constant 152 N/m which is then set into oscillation on a surface with a small coefficient of kinetic friction. The mass is pulled back 34.6 cm to the right and released. On the first right to left oscillation...

How would one calculate the drag on a projectile (in this case a 1cm3 cube) that was launched at 0°. The vertical drop, initial velocity, distance, and time (taken to travel distance) where measured. I want to say that I could compare these experimental drop (bellow hight that projectile was...

Hello everyone, this is my first post so I don't know whether or not this is the right thread to be asking this question (if so I am sorry). I am currently working on my thesis where I am determining the thickness of a GaN crystal through second harmonic generation. However in a article...

Homework Statement We did a Prac where we attached ticker tape to a cart (905g), and the cart to a mass (249g) through a pulley. We then had to assess the tape and answer questions. We are asked to calculate the force acting upon the whole system and then calculate the force acting only upon...

I am trying to estimate the amount of electrical power needed to heat up a material from 20C to 1000C in 20 seconds. Assuming it is 18sqin and 3mm thick, I used the specific heat which was given as 0.78 J/gC and weight 11.39g (from the destiny of 3.26). 0.78 J/gC x 11.39g x (1000C - 20C) /...

Hi all, I am very new to physics and have little to no background in engineering, however I am a biochemistry major whoe somehow wound up in material research lab. One thing I am having trouble understanding the thermal expansion coefficients, how they relate to each other and which one I...

Hi! I have a problem: I need to solve an equation, Ax=y, where A is a known matrix, y is a known column vector and x is an unknown column vector. Unfortunately, A is singular so I cannot do the simple solution of inverse(A)*y=x. Does anybody know of any way that I can obtain the coefficients...

As I have looked through the internet and did my research I have found some information on how to calculate the drag coefficient, however none of what I have search for matches what I need. Currently I am doing a physics assignment for grade 12 and I am investigating the physics behind...

Hi all! I'm analyzing a fermenter and the water cooling system that cools it down. In analyzing this I've found kW and kWh required to cool down the fermenter using Q = dt*cp*m However when I try to find the overall heat transfer coefficient U using the data, I find that it varies with...

I was wondering what would be the car mileage, if we reduce the current Drag coefficient from 0.30 to 0.15? Or to 0.10?

Goodmorning everyone, is there any implies to use in general relativity a metric whose coefficients are harmonic functions? For example in (1+1)-dimensions, is there any implies for using a metric ds2=E(du2+dv2) with E a harmonic function? In (1+1)-dimensions is well-know that the Einstein...

Homework Statement Homework Equations N/A The Attempt at a Solution Usually we are given a table, but how do we calculate the loss coefficient between 2 different pipes with different diameters? In this case, between the 5 and the 3 cm^2 pipes?

Homework Statement Hi, I was wondering how you would isolate for and calculate the coefficient of friction in an Atwood pulley, with one fixed pulley, with two masses hanging off of it on either side. There is no table or surface that the masses are touching or resting on, they are both...

In Vol. I Ch.33 of Feynman's Lectures (http://www.feynmanlectures.caltech.edu/I_33.html), 33-6, the reflection coefficient as a function of angle was derived. I am confused about the part where it said the component of A perpendicular to B (Acos (i+r)) has the right polarisation to produce B...

Hi. I am stuck on a project on calculation of heat convection transfer coefficient for a annular finned pipe. All parameters [Diameter of pipe, diameter of fins for each case, the distance between fins, fin thickness, pipe length and fin number] are determined. And I have two book Fundamentals...

Why is the coefficient of restitution of a ball independent of the height it is dropped from? A mathematical explanation would be best. Thank you.

Hello, I'm about elaborating a discrete mass-spring model to describe the vibration of a thin isotropic plate. For the flexion i choose a kind of spiral spring in the two directions X and Y: so the momentums will be Mx= Cbx.(Delta Thêta) ; My = Cby.(Dela Psi). and the energies: Eb =...

I have some time series data of the absorbance of Br2 formation using UV Vis spectroscopy and I need to figure out the extinction coefficient/ absorptivity. The overall reaction is BrO3-+5Br- +6H+-->3Br2+3H2O which is expcted to go to completion I know that the equation relating absorbance to...

Homework Statement This is for differential equations with nonconstant coefficients and I wasn't so great at series and sequences in calculus so when I came across this example problem I wasn't sure how they got to their final form. If someone could explain it to me that would be really...

I have a problem with Discharge Coefficient of Valve equation which is described in book 'advanced water distribution modeling and management' let me say: I think the expression V^2 in Discharge Equation (P. 618 of the book mentioned) is extra and the equation must be changed to: I)...

Hello everyone, I am predicting the altitude of a model rocket based on some testing I did where I found the impulse of a little single stage model rocket motor. I am wondering how to incorporate drag into my calculations to make it more accurate. I know D=Cd*rho*v^2*A and I can definitely find...