Dynamic Definition and 478 Threads

I've been reading about this but I couldn't find a conclusive answer. I have to measure the spring constant (k) using a vertical spring-mass (M) configuration and using two different methods: - static method: I calculate elongation vs weight and find a linear fit of the data (the slope is K) -...

I want to know that are there any materials or methods by which their relative magnetic permeability (μr) be instantaneously,continuously & periodically varied. Kindly provide the reference document/video for the description if possible.

1. Homework Statement Homework EquationsThe Attempt at a Solution This is what I did: Since they said at equilibrium, the total no. of moles is (2+x), so P and Q should have 1 mol each at equilibrium. So P and Q are in 1:1 ratio, but how do they know x is 1 ? Ans is B

Hi, I am proficient in standard dynamic programming techniques. In the standard textbook reference, the state variable and the control variable are separate entities. However, I have seen examples in economics, in which a single variable, let's say consumption, is both a state variable and a...

Hello, Normally a pitot tube points in the direction of airflow so that it measures static and dynamic airflow. If it points in the opposite direction my assumption is that it will not measure the dynamic pressure but will only measure the static pressure. Is this correct?

Homework Statement I need to create data structure which contains three linked lists that are connected to one root node. Homework Equations -Data structuresThe Attempt at a Solution I can't find what is wrong with the following code: #include<stdio.h> #include<stdlib.h> typedef struct node {...

When I see a paper where it is explained the wind effect on an airplane, I always see a kinematics problem. Now I'm interested in calculating the wind effect starting from the force that the wind exert on the aircraft surfaces. I know that F= 0.5 * rho * V2 * A * C and I also know that if we...

Homework Statement The conical bearing is placed in a lubricating Newtonian fluid having a viscosity μ. Determine the torque T required to rotate the bearing with a constant angular velocity of ω. Assume the velocity profile along the thickness t of the fluid is linear. Homework Equations v=ωr...

So I was sitting around pondering about forces, and I found myself thinking about shock-waves. Whether they're caused by supersonic travel, or explosions, the pressure at the front of the wave-bow shock pressure is a force. So I started thinking of a way to generate them without having to go...

Hi, I have to make a project for school about the topic on the title. It must be a personal work, i mean i can't choose a difficult subject cause then all my presentation could be just a simple documentation. Also, the project could include just one or two of the topics in the title. I thought...

Homework Statement I have a binary tree. I need to print a path of a doubly circular linked list (0 and 1) after every user input. I have a code in which user inputs data about one person. For example, when user inputs 2 elements, the path should be 0->1. In my code, it won't print any path...

Hi guys, after hours of searching internet I couldn't find much real-life examples of second order nonlinear dynamic systems (only tons of tons of equation and system theory... got totally frustrated). They will serve as a base process for modeling controllers. So far I found propeller pendulum...

http://t.co/XkVpUrtuAA BTW, how to insert a photo url to show an image here at Physics Forum? http://www.dumpt.com/img/viewer.php?file=yfxl69kwf7oisplu6gzw.jpg

Hi PF! I'm using a finite differencing scheme to solve the following $$h_t = h h_{zz} + 2h_z^2$$ where the subscripts denote partial derivatives. The difficulty I'm facing is the boundary conditions are dynamic, and move with time ##t##. This makes choosing a ##\Delta z## very difficult and...

I'm fascinated by the prospect of them, but I can't seem to find much information/progress online aside from like small sensors which aren't quite the same thing. Has there been anything developed that is a self powered vibration generator? As in, it vibrates and then is powered by its own...

I was receiving help for the following problem... The 2.0 kg wood box in the figureslides down a vertical wood wall while you push on it at a 45 ∘ angle. The coefficient of kinetic friction of wood on wood is μk = 0.200. What magnitude of force should you apply to cause the box to slide down at...

Do the orbitals of electrons change positions within their energy level relative to the nucleus or are they statically "attached" to the nucleus? To try and put this into perspective, would the orbitals of the electrons be like nailing a balloon(orbital) straight to the ball(nucleus) or nailing...

Hello! (Wave) I am looking at the following example of Memoized Dynamic Programming algorithm. memo={} Fib(n): if n in memo return memo[n] if n<=2 F[n]=1 else F[n]=F[n-1]+F[n-2] memo[n]=F[n] return F[n] Could you explain me why we check if $n$ is in memo although memo is a set...

Hey everyone, At the moment I am stuck with an example and was wondering if someone could please explain it to me: You have the equation: BiOCl(s) + 2H+(aq) -><- Bi3+(aq) +Cl-(aq) +H2O(l) Why is it that when you add extra water to the system, there is no change to the equilibrium? I would...

Hi, I have read the static equivalent model of distribution system with high penetration of PV systems, using ZIP modelling technique. Now I want to create a dynamic equivalent model of distribution grid with high penetration of PV systems. How should I proceed?

Homework Statement Derive from the formulas ##\frac{D^\pm}{Dt}(u \pm F) = 0## where ##\frac{D^\pm}{Dt} = \frac{\partial}{dt} + ( u \pm c) \frac{\partial}{\partial x}## the one-dimensional wave equation in the acoustical limit. \begin{cases} u << c\\ c \approx c0 = const\\ F =...

Can anyone make a recommendation on a good first course book on Dynamic Mechanics? I have a good background in calculus (1,2,3,ODE's,PDE's), linear algebra and statics (up to and including bending/shear moment diagrams etc.). So anything that makes use of those maths and sciences would be...

I've got the following problem which I need help with. I'm used to calculating coefficients when the problem is about ellipsoids and first order approximations. But when it comes to spheres and coefficients J_n I really don't know how to approach the problem. Can somebody help me out? Consider...

Homework Statement Brittle materials as glass and ceramics have generally a much lower tensile strength than compressive strength. A rigid mass impacts the end of a bar (free-free) of such a material and a piece of the other end drops off. Is there a relation between the length of the piece...

Homework Statement y(t) = e^{a(t-t_{0})} y(t_{0}) + \int_{t_{0}}^{t} e^{a(t-\tau)}b \dot{u} (\tau) d\tau u(t) = \delta(t) = \frac{1}{2} c^{3} t^{2} e^{-ct} where c >> |a|, t_0 = 0, and y(0) = 0 Find y(t) and represent the unit impulse, delta, in the solution. The remaining terms should not...

It seems like there are people working on dual formulations of fundamental interactions (dynamics, kinematics) all over the place: Quantum Spin Foams, Lattices, Energetic Causal Sets, Holographic Boundaries. Wondering whether anyone can point toward theoretical research looking at fundamental...

The previous threads are too old to reply to, so here's a link to a video of a radio control glider achieving 505 mph, which I think is the current record. The wind speeds were 50 to 62 mph, with gusts up to 68 mph. Near the end of the video, the glider drops out of sight of the camere due to a...

Hi, I currently have a project running involving dynamic insulation. I am struggling to develop a 1D transient analytical model to compare to my experimental results. I have used the separation by variables method in the most basic form over 1 solid material but have failed to adapt this to 3...

Homework Statement Hi I have attemted to work out the undamped natural frequency and the damping ratio can someone please confirm if this is correct? and for question d I have worked out r and TR can someone please confirm if this is correct? if all is correct I need help with plotting a graph...

Hi, i am trying to find the natural period of a vertical cantilever beam which is fixed at bottom and free at other end., i worked out the global M & K matrices and i have the eqn in the form [M]-w^2[K] = 0, the M & K are not diagonal matrices, but square symetric matrices of rank 6. i...

I am trying to crop an image and be able to manipulate in some way (I adjusted contrast) and show change in formatting as its displayed beside the original image (by making it turn more and more blue). The code runs successfully, but it seems to already have made the cropped image as blue as...

Hi guys, I was studying dynamic light scattering experiment and I had a problem! Here's the thing: I read that in case of weak coupling between x-rays and matter the whole system behaves as a linear system. I knew that linear systems respond to an input signal with an output that has the same...

This is not a homework question, just a simple physics question which I decided to ask here. I held off from asking in the other general physics forum because I get accused of asking random questions that are insignificant. I really want to understand these terms and how they are compared in...

Homework Statement A 2-D nozzle shown in picture 1 is to be analyzed. The nozzle is working with critical condition at the throat. I haven attached a Pdf and .jpg file for the figure ReD* :230000 D* :6mm T0 :300 K Diffusor half angle : 3° Diffusor length :7D Medium :Air Κ :1,4 R...

I am making a basic structural engineering software program for modelling cylindrical pipes. I want to model the effect of fluid inside the pipes. For static fluid I let the user input the internal pressure and density of the fluid in each element. For moving fluid I additionally want to let...

For example, in chemical plants, if a pressure gauge is on a pipe and it reads 5000 kPa, is this a static or total (static + dynamic) pressure reading? I am thinking it must be the total pressure. Would that mean that a pressure reading in this setting is both a measure of static pressure...

I understand that the dynamic modulus of a material is measured by inducing a sinusoidal force and measuring the strain response. Usually one gets a value for the storage and loss modulus. However, I don't understand how one would "quantify" how viscous a material is. I know a viscous material...

Just a quick question. Let A and B be two points. Electrical work is defined as the amount of energy it takes to move an amount of charge Q through a potential difference VB-VA (for our purposes here, we will assume that the voltage values are measured with respect to an Earth ground) and is...

I have the summation (from i=0 to n) of (F_{t})(R) / (1+d)^i where F_{t} = (F_{t-1})[(R)(I_{p}) +(1-R)(I_{r})] (The F_{t-1} is referring to the value of F in the last period) I want to find the value of R that maximizes the summation. So must I take the partial derivative wrt R? How do I...

There are two ways I'm used to allocate memory dynamically. int * array = malloc(10 * sizeof(int)); But this type of memory allocation, have a predefined size, which is not desirable. I keep hearing about linked list and push & pop. I've reviewed them over and over again, and they just...

Homework Statement Suppose that we use a Michaelis-Menten growth rate in the chemostat model, and that the parameters are chosen so that a positive steady state exists. Show that N = f(V,F,C0) = (C0(F - VKm) + FKn)/(a(F - VKm)) and C = (FKn)/(F - VKm) at the positive steady state. The...

Good day. I want to ask for such a thing: If I put in a vacuum photon pulsed laser with a wavelength of 10 nm and against Casimir cavity of two metal plates with a gap of 10 nm. From the laser pulse will shoot photons in the cavity. Occurs dynamic Casimir effect? Thank you. Goodbye.

If I have a linear actuator, how can I find out how much force it can move with a constant velocity?

Hi there, I am currently a student at Heriot-Watt University and have been given a project of deriving a nonlinear equation of motion for an a380 wing engine. The engine is to be considered as a lumped mass attached to the cantilever beam and the main fuselage is considered having translational...

Given a set of n things (1,2,...,n), we want to group them in clusters that contain adjacent things. For each cluster there is a cost $c_{ij}$. We are looking for the grouping in clusters so that the total cost is minimal. I am asked to write this problem as a shortest path problem. What do I...

1. Hi All I had a quiz in my fluid mechanics class with the question A ship model scale 1/25 is towed through seawater at a speed of 1m/s. A force of 2N is required to tow the model. Find the speed of the ship if the prototype is subjected to wave resistance only. 2. REm=REp...

If we know that the Polarization P in LIH dielectrics is proportional to the net field inside the dielectric according to: P = ε0χeE...(1) And we know that D = εE...(2) Does it not follow that we can ascertain the polarization directly from the applied (free charge) field, since we...

Homework Statement What does Q-factor and Dynamic resistance of a parallel resonance circuits mean?Homework Equations The Attempt at a Solution In general, their performance is measured by a dimensionless parameter named quality factor Q, which characterizes the sharpness of the resonant peak...

Please see attached for question. My problem is the initial displacement. i am told the first step is this kx + c(dx/dt) = unit impulse laplace transform kX + c(sX-x0)=1 from that i can see the initial displacement is included in the damper but why isn't it included in the...

static balancing is when the center of gravity is in the axis of rotation. dynamic balancing is when the central principal axis of inertia is parallel and coincident with the axis of rotation. my question is, even if its theoretically, can you have dynamic balancing without static...