Virtual work Definition and 70 Threads

  1. mishima

    Misc Questions: Virtual work, RMS, Friction on incline, and Virtual Displacement

    I have a few questions I thought I'd post together instead of making separate threads, hope that's ok. They are more or less unrelated... 1. Are there 2 conceptual ideas that use the term "virtual work"? I am familiar with the one from intro level physics, but I read there is also one from...
  2. C

    Does Rope Position Affect Acceleration in Rotational Movement?

    I refer to the figure: Is it true that affixing the rope at the point A isn't the same of affixing it at the point B? (I consider the rotation movement around O since the disk is rolling, and so the radius of rotation is different in the two cases) I'm sorry because my english is not very...
  3. R

    Active Force Diagrams/ Virtual Work

    Homework Statement Homework Equations ? The Attempt at a Solution a) y=2Lcos(θ) x=2Lsin(θ) b) I haven't started the next question as I want to make sure the active force diagram is correct first.. If somebody could just check the diagram and help me with where I'm going...
  4. M

    Statics 2D Virtual Work problem regarding calculation of Normal force

    PROBLEM 1 Homework Statement The frame in the figure is supported by a hinge in A and a roller in G. It is loaded by a couple = 14 kN*m in B, a force = 12 kN in D and a distributed force = 4 kN/m on section EG. = 1.4 m. Calculate the normal force in C. Use the correct signs...
  5. M

    Conservation of Energy and Virtual Work

    Hi, I've been reading chapter 4 in the Feynman Lectures on the conservation of energy and I've bought a book off amazon called Exercises in Introductory Physics which accompanies the series. Having looked at some of the questions I feel well out of my depth because essentially I haven't ever...
  6. B

    Virtual displacements and Virtual Work

    Hi all, I am having trouble understanding Virtual displacements and related ideas and would appreciate your help! Let's say we have a simple pendulum and we take a snapshot of this system at some instant of time : A 'virtual displacement' is said to be : - consistent with the constraints on...
  7. L

    Dynamics (mechanics) and virtual work

    Hi everyone, I'm studying applied dynamics for college. I have a simple question and then a more importante question: F=dq/dt=ma (torque)T=dL/dt What do you call these equations, Newton-euler equations? I use these equations all the time to relate forces and torques with motion, in certain...
  8. A

    Principal Virtual Work vs Principal of Minimum Potential Energy

    Hello Just had a quick question for a structures class. When attempting a problem, what's the main difference between applying PVW and PMPE? What would classify a problem in using one over the other? Thanks
  9. C

    How Does the Principle of Virtual Work Apply to Particle Equilibrium?

    I could not understand the Principle of virtual work. Suppose we have two (x,y,t) [at two different points].By principle of least action we will get a trajectory such that it minimize lagrangian. Does the principle of virtual work say that it will vary the path a little but having the same...
  10. A

    Rigorous statement of virtual work principle?

    rigorous statement of virtual work principle?? in the texts on mechanics the virtual work principle is always stated in 'infitesimal form'. is there a "proper" way to write the principle of virtual work in which we don't leave it in terms of INFINITESIMALS.
  11. S

    Principle of virtual work invention

    i want to throughly understand the principle of virtual work. why this principle was invented? "sum of work done by forces is zero". such a definition is very vague for me. can anyone explain?
  12. M

    Need help to solve hyperstatic system problem by Virtual work method

    Homework Statement anyone guide me step by step how to use virtual work method to calculate all reactions on this beam? thanks Homework Equations The Attempt at a Solution
  13. D

    How Does the Principle of Virtual Work Determine Structural Reactions?

    using the principal of virtual work, find the reactions of the following structure as far as i know, to solve using virtual work i take the statically determinate structure and release one of the support reactions making it indeterminate (1st degree), after picking my brain with the...
  14. A

    (Beam theory) Deriving Virtual Work

    Homework Statement Derive the equation used for calculating the deflection of a beam at some arbitrary point. Because I haven't seen anything like this on the web or in textbooks, I am asking for some feedback. Homework Equations v_{k} = \int\frac{\delta M(x)M(x)}{EI} dx The Attempt...
  15. J

    What is virtual work? And how does it apply to this question?

    Hi All! I am new on here so I hope you quality people can help me out:) I have this question and it asks me to solve it using Virtual Work? What is that and how do I apply it to this question: "A slender rod of length L is attached to a collar at B and rests on a portion of a circular...
  16. T

    Virtual Work - Magnetostatics - Feynman?

    In reading Feynman's "Lectures on Physics", volume 2 I have a question and have included a scan of a small section from the book. Feynman was a big fan of using the Principle of Virtual Work, but his explanation, as least insofar as how he used it is wanting, at least for me. The attached...
  17. S

    Solving an Indeterminate Beam: Virtual Work Approach

    How do you go about solving an indeterminate beam for various deflections by virtual work? I'm kind of at a loss right now and can't proceed on my homework. I've attached a picture showing the problem I'm confused on - I don't know how to go about modeling the virtual model so I can find the...
  18. H

    What is the best way to draw diagrams for virtual work on rigid bodies?

    Homework Statement Im having real trouble with drawing diagrams for virtual work. Can someone please, please help me! We were asked, in the diagram i posted, to find 1)vertical reaction at F, 2) all reactions at A, 3) bending moment and shear force at B using virtual work. i think i...
  19. L

    Principle of Virtual Work and Feynman

    I was just reading the Feynman Lectures on Physics when Feynman discussed virtual work. Unfortunately, I found his explanation somewhat confusing. The following are the three examples Feynman uses in order to illustrate the principle of virtual work. 1. 2. 3. I'm trying to...
  20. C

    How does the principle of virtual work apply to solving statics problems?

    what is the principle of virtual work. In what circumstances this can be used to solve statics problems?
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