Dynamic Definition and 478 Threads

I have been looking into how the overall viscosity of a liquid/gas is related to kinematic and dynamic viscosities. I have used nwater = 1e-3 Pa.s nair = 17.4e-6 Pa.s densitywater = 1000 kgm^-3 densityair = 1.3 kgm^3 and kinematic viscosity v = n/density So vair ~ 1.4e-5 vwater ~...

Hello again, Physics Forums. I'm designing a Sci-Fi story and I'm fleshing out the background details. For it's sake, education, and my own curiosity, I was wondering if I could have some help with a few things related to the physics of it. A bit of an armchair Rocket Engineer, I'm using...

Hi ! Sorry for a naive question from a biologist. I am making proteoliposomes within which a fluorescent probe, pyranine (lex = 455 nm, lem = 509 nm), has been trapped. I try to quality control my preparations using DLS (Dynapro, Proteinsolutions) and my concern is that whatever the...

(or "circular motion" problem) Okay, our lecturer pretty much has thrown us into cold water here. My big problem is getting the right list of formulas. I'm not sure this is a homework problems since I'm stuck in preliminary stages. Homework Statement...

Hi All, I am trying to get an analytical solution to a contact problem with dynamic loading. I am not sure if an analytical solution of such a problem is possible. Here how the problem is: A cantilever beam, with its free end resting on a smooth plane, is under harmonic loading f(t)...

My Semester Project Is "Dynamic Analysis of Wind Turbine Blades" In ANSYS 9 Environment ... I've Modeled Wind Turbine 'Rotor Assembly' In Pro|Engineer And Successfully Imported Into ANSYS ... I've Practiced 'Static Analysis' Only In The ANSYS Environment ... So It Leaves Me With A ZERO-LEVEL...

Homework Statement A leg has a horizontal propulsive ground reaction force 200N and vertical ground reaction foce of 1200N applied to it. Draw a free body diagram. The leg has an acceleration of -4m/s2 in the x direction and 8m/s2 in the y direction. What are the horizontal + vertical...

hi colleages...is the equation below represent a dynamic equilibrium of vibrated beam-column member and simple boundary conditions? M(x,t)=Q(0,t)*x+integral{q(x,t)-mass*acceleration(x,t)}*(L-x)dx where M(x,t)= dynamic moment. Q(0,t)=shear at x=0. q(x,t)= external dynamic loading...

Hi guys, I'm a pure math master degree. Interested in studying dynamic systems, I want to learn more about this subject without any academic course.(just self study) How can I start it? Which books , articles and subjects?

Sometimes we need to calculate the evolution of the scalar field \phi with the equation of motion \frac{\partial^2 \phi}{\partial t^2}+3H\frac{\partial \phi}{\partial t}+m_\phi^2 \phi = 0. And we can get the field \phi=Ae^{im_\phi t} where A is the amplitude of the scalar field (damped by...

Hi everyone. I've been out of college for some time and forgot how to determine the shape of a droplet. I know how to determine the contact angle based on the interracial energies of three mediums, but I'm not sure how to calculate the actual shape of the hanging drop. In my scenario I have a...

Hello, I'm quite new to the concepts of quantum theory. So as such I have an interesting quandary. Keep in mind that I don't have as much back ground in study of physics as the lot of you but I will try my best to explain my dilemma. Given 1)Both the electron and nucleus have a charge and...

Problem Statement A 50cm by 30cm by 20cm block weighing 150N is to be moved at a constant velocity of .8 m/s on an inclined surface with a friction coefficient of 0.27. (a) Determine the force f that needs to be applied in the horizontal direction. (b) if a .4mm thick oil film with a dynamic...

Could someone please help? The question reads: For which real numbers "k" is the zero state a stable equilibrium of the dynamic system (vector(x))(t+1)=A(vector(x))(t)? A= [0.1 k ## 0.3 0.3] --> a 2 x 2 matrix with ## separating the two rows. So, my thought is I need to find the...

Hi all, (1.) Can someone tell me the difference between a compact valued and single valued correspondence? (2.) I have been seeing repeating themes of "continuity on a compact set". Does that imply boundedness and thus possible to attain maximum? (3.) What's the difference between...

Homework Statement Not sure why, but I opened an old textbook (Dynamics - Engineering Mechanics, Meriam, 1980) and started paging through. I decided to try this problem (attached jpg) and got stuck. The problem asks for the acceleration of the center of mass of the system of 4 weights...

A simple question, but I can't find the answer anywhere :redface: … when something (otherwise unconstrained) is pulled by rope (approximately forwards) so as to slide (not roll) at constant speed in a circle on a rough surface, the total acceleration is obviously centripetal (radial) there...

what is a the difference between a static and a dynamic impact?

Is there a valve that can be set to open to let hot gas out at a certain pressure, and then close once the pressure drops back down? Edit: Sorry, I'm looking for a valve that will let the pressure build up to a high point, then open to release the gas until the pressure is released, then close...

Please refer to this website: http://www.grc.nasa.gov/WWW/K-12/airplane/dynpress.html" In the "Simplify" step, where does the factor of 1/2 come from? I must be missing something simple... Thanks for the help!

I need some help estimating the heat transfer of a system. If I have an exposed length of pipe with a dynamic fluid moving at a constant volumetric rate through a very hot room, what equation is most appropriate to calculate the exit temperature of the fluid? Given: Initial temperature of...

hi colleages. is Bernoulli-Euler theory valid in the dynamic analysis as following: M/EI=1/R where, M= moment EI=stiffness R= curvature is this equation valid when M becomes a function of x and t, as follows: M(x,t)/EI=1/R

I'm starting a project involving a venturi and water, and for the venturi, I need the water pressure to be around 7-10 psi. This means for my water pump, the head height must be around 15-20 ft. Most pumps that fulfill this requirement are either too expensive or are too powerful for my...

I am about to talk to a prototype company and need some advice on O ring, friction and seals. I am creating a device that works on slight water pressure differential. I have a piston like structure that is cylindrical and there will be an o ring inside the cylinder. The gas/liquid that the o...

this function is supposed to find the first item in an array that is less than the element preceding it, and set the p parameter to point to that item, so the caller can know the location of that item. when i run it.. it fails. there are probably multiple bugs.. any suggestions on how to fix...

Hello everyone, I have a problem with 4 degrees of freedom, 2 of which are superfluous. My goal is to derive the equations of motion. I have derived the equations connecting the superfluous DoFs with the independent ones, however they are nonlinear and interlaced, which means that I cannot...

Homework Statement I'm trying to learn the dynamic system model, I was given the following problem to work with. Can someone give me a walk through of did I did right or wrong? Situation: A conservationist is studying a colony of endangered variable oyster-catchers. Birds that are chicks...

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Hi, 1. I am studying dynamic light scattering in which one experimentally measures intensity correlation i.e., <I(t)I(t+tau)>. Therefore, if the detector looks at a scattering signal from a solution of particles undergoing Brownian motion, under right experimental conditions one can detect the...

i posted it in general physics and got not answer. maybe this is the right place for this. thanks here is a question for max dynamic factor for sinusoidal load F*sin(at). say the natural frequency is b for a mass. then the max DLF considering damping is DLF=1/(1-(a/b)^2) when a>>b...

A motor vehicle has a mass of 700Kg and is traveling at 36 km/h on a level road; it is taken out of gear and allowed to roll to a stop. The first part of the question asks me to work out the kinetic energy which I've done and then the next part asks how far will it travel if the rolling...

When I studied the fluid dynamic , I saw a quite hard equation (typed in attached file) , I don't know how to prove it , maybe there's a somehow relationship between this eq with Gauss's Divergence Theorem ... Can anyone help me ?

Should the static spring constant and dynamic spring constant of the same spring be the same value (or very close to the same value)? I know the difference between the two is that static is found by measuring the displacement from equilibrium by adding different weights and dynamic is found by...

I'm trying to conceptualize a design for a hydro generator that basically operates by moving an airfoil up an down along a straight path. Most of it is all worked out, except for the issue of water sealing. If you can make sense of my not-so-great drawings, the airfoil is attached to the...

a train of mass 240 tonne is moving, at a speed of 84 km/h, up an incline of 1 in 90. the resistance to motion is 45 n per tonne. if power is removed, calculate the distance traveled along the incline before the train comes to rest and a railway wagon of mass 10 tonne traveling due east with a...

Homework Statement A light spring having a force constant of 125 N/m is used to pull a 9.50 kg sled on a horizontal ice rink. The coefficient of kinetic friction between the sled and the ice is 0.200. The sled has an acceleration of 2.00 m/s^2. By how much does the spring stretch if it pulls on...

IMP! how to perform a dynamic thermal analysis on ANSYS? I have to simulate a model having an alumina pin on a rotating steel disc to calculate the surface contact temperature of the pin in ANSYS, and to give rotational speed to the disc LS-DYNA has to be used. But thermal analysis cannot be...

Homework Statement http://img689.imageshack.us/img689/2315/dynamicsproblem.jpg" Homework Equations The Attempt at a Solution FC = FfB mC * 9.81 = (6.0)(9.81)(0.30) mC = 1.8 <---- :( Obviously that was wrong haha. I then tried to figure out how the pulley affects the...

Placing a block of metal in a solution of its ions causes it to go into some kind of dynamic equilibrium such that the metal ions form from atoms and atoms from ions at the same rate. In the first place why does this phenomena occur? Is it something that can be described using Physics...

Hello, I have a little question regarding airflow. You have an object in a wind-tunnel, which has a dynamic pressure of 1000Pa and say static pressure of 99000Pa. If the object has a duct with static and total pressure probes, to maximise airflow through that duct, would you be looking for...

just wondering if someone could explain the difference between a static and dynamic collision is. I am trying to model a side impact crash between 2 cars and just wondering why it would not be accurate using a static collision. i.e. applying a static load on the door in an FEA

I completely made this question up because it's related to class and it will help me understand the lesson better and more. Explain the work of scientists and how they revolutionized scientific thought. Include Max Plank, Einstein and Michelson-Morley. The work doesn't have to be only about...

[b]1. Machanical Prinisiples assignment. Homework Equations Hi guys, i am a new member here, and am really looking for some help. My question is: A wheeled truck has a total mass when loaded of 1500 kg and is to be hauled up an incline of 1 in 1o (sine). g= 9.81 m/s2 and the...

I've read small bits of Tesla's Theory of gravity., but nothing in detail. Does anyone actually know how he explained the phenomenon of gravity? I know this is a vague question, and I don't know exactly what I'm looking for, but any information on the basis of why he rejected Einstein's General...

Gday fellow engineers, I have what I think is a rather trivial problem but would appreciate feedback on it. What I am working on is a mechanical model measuring the force of an object (eg a paddle pop stick or something else) along one axis of motion once a force is applied to it, causing it...

I'm interested in doing an experimental analysis of ribbon transducers to contrast with simulations. This data could be made available to the community to aid in transducer development. A ribbon transducer consists of a rectangular element of metal foil suspended within a magnetic gap and...

Hallo. I am new at forum, could please somebody send me a code for fluid dynamic in 3D written in Scilab, mathematica or Fortran. I will use it to start with learning!b Thaks, JG

hello. can anyone help me find information about "dynamic hardness measurements" ? a direction to books or websites will be very helpful... thanks

Homework Statement I am asked to provide an anti vibrational support mount for equipment mounted on turbo-prop aircraft. The equipment has a mass of 40kg. the vibrational response of the equipment to the environmental disturbances will need ot satisfy a safety limit prescribed by the...

From the stupidity that brought us the cordless jump rope, we have the shake weights. I'm sure you've seen/heard the jokes being made about the suggestive motion you make while using these. You might as well pickup a brick and shake it. https://www.shakeweight.com/ver5/index.asp