Dynamic Definition and 432 Threads

Hi, I would like to clarify this probably trivial little issue that is bugging me: How should dynamical solutions be understood in the context of a static spacetime? To exemplify what I mean I'll use a well known case, the source-free Maxwell eq. in their explicitly covariant form set in...

Hi! Slightly oddball request. A nice, but mistaken guy has produced this website-http://www.dynamic-soaring-for-birds.co.uk/ and further written about his ideas here-http://www.bou.org.uk/dynamic-soaring/ He contends that Dynamic Soaring is possible utilising a constant horizontal...

The 20-kg sphere, attached to a spring of stiffness 500 N/m is released from an un-stretched position of the spring, as shown in the figure. Determine the velocity of the block “A” of mass 10 kg, at the instant the ball has fallen 25 cm. A roller mechanism keeps the spring in a vertical...

I'm thinking about doing online tutoring. I already know how to use latex on a website but I need to be much faster for a live tutorial session. Is there a way that I can write my math down on a tablet and have it automatically converted in rich math text and also have it automatically...

Hi all, I have a ground excited single degree of freedom model, like that: http://www.bsw-schwingungstechnik.de/fileadmin/user_upload/images/2/graphic-passiv-isolation.jpg I know the excitation function, i.e. s(t), but I need to know the force that imposes a specific s(t). I need it...

Homework Statement As part of a larger problem, I'm trying to understand the dynamic equations of the attached circuit with two capacitors and one resistor and a voltage source. When I use Kirchoff's Current Law at nodes V0 and V1, I get the following equations. Homework Equations See...

Hello, As part of a larger problem, I'm trying to understand the dynamic equations of the attached circuit with two capacitors and one resistor and a voltage source. When I use Kirchoff's Current Law at nodes V0 and V1, I get the following equations. 0 = (dVs/dt-dV1/dt)*C1 - (V1-V2)/R -...

Homework Statement in a cylinder, 1.2 mol of an ideal gas, gamma = 1.67 initially at 3.60 x10^5 pa and 300k, is compressed until the volume is halved. I need help with 1) c and 2) Compute work done on the gas if the compression is: 1) a) isothermal b) adiabatic c) isobaric...

This I something I always wondered, but never could get my finger into: ##a_m = \frac{v_2-v_1}{t_2-t_1}## Alright, that's medium acceleration, but why isn't it: ##a_m = \frac{a_2-a_1}{t_2-t_1}## I mean, it does make perfect sense in my mind. Is it just because it was defined that way?

What makes objects in dynamic equilibrium move? It can't be gravity because then it would only be one force and if an object is under the influence of one force, then it cannot be in equilibrium. Any help would be appreciated.

Homework Statement if the equilibrium rule states ƩF=0N, how can something move or be moving at a constant speed ? eg I push on a box with 50N and friction provides 50N back, resulting in ƩF=0N. So I am not providing more N than the box is resisting with. I thought something could only be...

Please take a look at my program. Please help. I want to allocate memory dynamically for one field in structure. I tried to write the code but it has error. I posting a paint document for you to see. Help me please. Please tell me why is my code not working properly and what needs to be done...

Hi, I have done an elementary search, but have not found the software I am looking for. I would like to work with page layout software that has the dynamic drag-and-drop WYSIWYG repositioning and textflow capability of Adobe InDesign, but that also allows inline LaTeX math typesetting and...

Hi. me and my friend have a problem that we can't really agree upon. we are doing an analysis study on a bike's crank and pedal. the first picture shows how we put the force of 210 N. picture 2 shows how we used "fixed geometry" to lock the part in place. now, this is the static...

Homework Statement Derive the Euler Equation of the dynamic programming problem: \[max_{\{ z_t \}^\infty_{t=0}} \sum_{t=0}^{\infty} \delta^t f(x_t, y_t, z_t) \] subject to: x_{t+1} = g_1(x_t, y_t, z_t), \ y_{t+1} = g_2(x_t, y_t, z_t), \ x_0 = x^0, y_0 = y^0 and where \delta <1...

A man drags a 67.0-kg crate across the floor at a constant velocity by pulling on a strap attached to the bottom of the crate. The crate is tilted 24.0° above the horizontal, and the strap is inclined 64.0° above the horizontal. The center of gravity of the crate coincides with its geometrical...

Homework Statement Ok, I'm learning C programming and I'm trying to create a dynamic 2D array. This is the code that seems to work in creating a dyamic array. I found it in a book. //rows and cols are values entered by the user when the program runs. int **(matA) =...

I'm having difficulty with this question In the diagram, the coefficient of kinetic friction between the 2.00 kg and the 3.00 kg blocks is 0.300. The horizontal surface and the pulleys are frictionless, and the masses are released from rest. (a) Draw a free body diagram of each block...

Homework Statement I am trying to allocate memory on the heap (free-store) for an array of characters using one of my struct members, which is a pointer. However, I am running into scoping issues no matter how I try to go about doing it. Homework Equations <data type> *<pointer name>...

Hello, I'm wondering how to name/open a file whose name is given by a string with an integer appended at the end, i.e., something in the style of the following. Thank you! int i = 5; ofstream fout; string s = "Hello " + i; fout.open(s); // write something to the file...

Homework Statement While I was learning about drag and lift on airfloils, I imagined a special airfoil which is fixed at a certain elevation and cannot move vertically (y axis) but can be rotated around its axis (z). Let's assume the direction of the flow to be the x axis. I try to predict...

For a general family of dynamic models, xk+1=f(xk), oscillation can occur; for example, the function xk+1=xn2-1 experiences oscillation under the starting value 0: (x2=x12-1=x2=02-1→x2=-1→x3=x22-1=x3=-12-1→x3=0) This type of oscillation must be capable of detection before actually pluggin...

Homework Statement http://img59.imageshack.us/img59/493/capturemml.png The Attempt at a Solution Here is my attempt. I assumed that both the man and the box would slide down the incline. (The box is the left diagram and the man is on the right)...

Maybe I've asked this before but I can't find the topic any more. I'm looking for a way to calculate the outgoing force of a taper roll between two spinning flanges. Staticly this is not so difficult by using the force of the flanges clamping the taper roll and the roll angle. When the...

Hi, Those of you familar with dynamic light scattering (DLS), will know that a common method used to obtain a particle size distribution is via a laplace inversion of the autocorrelation function. What I want to know is why? What does Laplace space have to do with DLS (I've only learned...

hello everyone I know that dynamic array is not supported in Verilog and Quartus. I want to know does anybody has an idea or algorithm to use instead of dynamic array. I mean I am searching for something that works instead of a dynamic array. thanks

http://www.icarusengineering.com/Dynamic-Soaring-and-SE.htm I am trying to validate dynamic soaring versus normal thermal soaring, but both are using thermals as the power source. Dynamic soaring would mean using 2 types of air masses. One in the thermal and the second one is the inflow to...

Hi, I need some help with allocating arrays dynamically. I have an array whose size keeps changing at each step - I start with a row vector and add another row vector at each step of a cycle. I need to use this new array for further calculations. I've been trying to declare the arrays...

Hello Phys Forum I’m trying to solve a dynamic problem that involves a cantilever beam fixed onto a support that experiences a time history load on the free end of the beam as shown below: / / /--------------------------------[] / / Cross section Beam is rectangular beam with 1m width and...

Can two massive particles have parallel spacetime trajectories? It seems that the answer is - no. And the closer they are the more they can't. But in that case we can't have static structure consisting of massive particles. Any composite structure would have to have something like phasespace...

Hello, I'm trying to make a sort of "system theory approach" to dynamic Maxwell's equations for a linear, isotropic, time-invariant, spacely homogeneous medium. The frequency-domain uniqueness theorem states that the solution to an interior electromagnetic problem is unique for a lossy...

[FONT="Arial"][SIZE="5"]It is stated that kinematic viscosity is the ratio of dynamic viscosity to density. can anyone elaborate it further that what are the uses of both types of viscosities and why we differentiate them.does dynamic viscosity reates with static fluid?

I have a Mathematics C assignment, with one question being about static and dynamic friction. But I think it fits this forum. Anyway, we need to conduct experiments to show if there is a difference between static and dynamic friction or not with three different surfaces. The weight of the...

The diaphragm in a dynamic microphone moves a wire coil in the presence of a magnet to induce a current related to the movement. Other types of microphones, like electret and condenser microphones have self noise - noise not attributable to the amplifier. I wonder if all of the "self noise"...

Hi; I'm a new user of molecular dynamic code LAMMPS and I have a problem when I want first to compute samples problems.I beg erverybody who have already work with lammps to help me. When I want to compute the first examples called COLLOID; an error occurs like: "invalid pair_style".I would like...

Homework Statement The central moments of inertia of the gears A and B as shown are 10 kg.m2 and 20 kg.m2, respectively. If the mass of the block C is mC = 50 kg and the system is released from rest, determine alpha A of the gear A fig is attachedHomework Equations The Attempt at a Solution...

If the ball were rolling uphill, the force of friction would still be directed uphill as in FJg. 1O.19b. Can you see why'? http://img252.imageshack.us/img252/4516/rollingm.jpg I always assume the friction is always in opposite direction of the motion.

Dear all, I have written a code for dynamic analysis of a mechanical structure. My primary purpose is to find natural frequencies of the structure. When I test my code for a cantilever bar whose natural frequencies are known analytically, I found a big difference between the the first...

Can static pressure be induced to becoming dynamic pressure through the use of "right-angle forces" with respect to particle velocities? I imagine that one could accomplish this with an ionized gas and a magnetic field. This would reduce the amount of work that is need to accelerate the gas...

Hi all, I need to do a dynamic structural analysis using finite element method and I have a question about the mass matrix. Question: I have the force per nodes and I need to calculate the displacement of each node at a given time. For this purpose, it seems that I need to distribute the...

I am designing a survey to gather data on consumer preferences for notebooks (school club charity project). The survey will contain only 10 questions about what notebook designs they prefer. Thus, I only want them to see notebooks they are likely to want. I am not sure how to set up the...

I do not if it is the right section, however hello I'm Antonio and I am Italian so I apologize for my English. I have a problem I'm trying to manage a mathematical modeling from a graphical point of view, (I applied chaos theory and the theory of earthquakes and using the concept of point...

Hi there. I've got issues. Big ones. I need to simplify this crane structure, and calculate the strength on cilinder |c1c2| when applying a vertical load on the crane's hook. The purpose of this is to find how much of the strength is absorbed by the first cylinder (and possible the second one...

Ok-I'm actually looking to settle an argument on another forum. I have turbocharged my 1979 Volvo 240, and converted to a later style motor. Instead of drilling and tapping the boss in the block for my oil return to the oil pan, I welded a 1/2" NPT bung into my oil pan. The approximate inner...

Hi I am solving some problems in fluid dynamics I came to this problem that I don't understand how to solve it. A piece of granite floats at the interface of mercury and water contained in a beaker (Fig.). If the densities of granite, water and mercury are ρ, ρ1 and ρ2 respectively, the...

I have attached another diagram, and in the diagram I show a round piston with a 1 sq ft surface area pushing water through the pipe out into to open atmosphere at 14.7 psi at a constant velocity of 75 ft/sec. There is a vacuum behind the piston, and I have calculated a 37.9 psi dynamic pressure...

Hi! Can anyone recommend a text that goes through calculation in fall time, rise time, saturation time and final rise time thoroughly with some examples provided? I've looked through microelectronic circuit design by Jaeger / Neamen, they briefly mention the concept at best but do not have...

I'm having problem to solve this problem in DP: Given 2 subsequences: X = {x1, x2,..., xm} and Y = {y1, y2, ... , yn} so `n <= m` and also `y1 <= y2 <= ... <= yn`. The goal is to find a sub-sequence of `X` (xi1, xi2, ... , xin) such that: sum(k is 1 to n) | xik - yk | is...

I am disappointed by the fact that receiver noise seems to be directly proportional to bandwidth. With a raised cosine shaped pulse transmitter the bandwidth is the more or less the reciprocal of the pulse duration. Short pulses mean large bandwidths and that means greatly reduced range, at...

In a project I'm working on at school I could only get static acceleration from the 3-axis accelerometer I have (MMA7361L). I used a simple set-up (4 pins: Tx, Rx, power and ground). As far as I understand, accelerometers are able to detect both types of acceleration but I don't know why I...