Stability Definition and 524 Threads

Homework Statement A steel girder with a mass of 1000kg and a length of 10m rests on a concrete slab, with 4m overhanging the edge. How far can a 100kg man walk on the girder? The Attempt at a Solution I supposed that the right end of the slab is the fulcrum (rotating point), and...

how is aspect ratio of a wing related to longitudinal static stability (LSS)? like, if we increase the aspect ratio, is it going to increase or decrease the longitudinal static stability (LSS)? suppose we have an aircraft whose centre of gravity is fixed at a particular location, if the...

Just for the record: http://newscenter.lbl.gov/press-releases/2009/09/24/114-confirmed/ Cal Pride! :biggrin: Does anyone want to explain specifically how or why there is an island of stability?

Homework Statement In natural water containing 0.9 mmol/L calcium and 12 ug/L fulvic acid, determine the fraction of the fulvic acid that is bound to calcium (i.e. the ratio between the concentration of Ca-FA and total concentration of FA binding sites), assuming that calcium is the only metal...

I am trying to analyze the stability of a particular component of a non-linear differential equation system. It is a dynamical equation and the criterion for instability of a particular axis will help me determine whether there's a drastic switching event in the solution. My solution is a time...

Homework Statement You go to a quick – fix garage to get your brakes worked on. When your tires are re – installed, the mechanic forgets to put the lug nuts on your tires. Although nobody gets hurt, a tire comes off your car when you are traveling fairly rapidly and it is able to roll...

I was reading this on wiki: http://en.wikipedia.org/wiki/Lagrangian_point In the stability section, it claimed that for L4 and L5 to be stable the following must hold: \frac{M_1}{M_2}\geq24.96 Why is this the case? Where can I find proof?

"The rather strong acidity of trichloroacetic acid is usually ascribed to the inductive effect of the three chlorine atoms attached to the end of the molecle opposite the acidic proton. Electron density is withdrawn away from the carboxylate group so that the trichloroacetate anion that is...

A hydrogen atom is consists of a proton (uud quarks) and an electron. Is there a heavier atom of hydrogen that consists of a type of proton (ccs or ttb quarks) and a muon or tauon respectively? Are these

A considerable portion of E. Antarctica ice (average of 1.6 km height) rests on bedrock of 2000+ ft above sea level. https://www.physicsforums.com/showthread.php?t=344123" Would such a core suffice to cover enough glacial and inter-glacial periods; giving an adequate sample? Would any evidence...

If "unzipped" PNA and DNA combine to form a double helix, will the hybrid be more or less stable than a pure DNA double helix? This was a question on my chem homework (in a section on intermolecular forces), but I'm posting in this section as I already turned in the homework so I'm asking more...

Hii, First of all, I'm from Brazil and my english is not so good! I've been studied the follwing problem for some months and until today I'm not find a solution! Please help me. I have some blocks (2D) stacked like in the figure below (attachment). In each block I have ONLY the weight...

I've just learned by chance about http://en.wikipedia.org/wiki/Earnshaw_theorem which states that point charges cannot be maintained in a stable stationary equilibrium. But then, what does the negative electric potential energy (in this thread ...

Alright, there's something I don't understand. The book says that the gain margin and phase margin must be non-negative for a minimum phase system to be stable. But the definition of a minimum phase system is one without right half plane poles or zeroes. Doesn't that inherently make it stable...

Neutrons bind Protons in nuclei, and/or the other way around, but why don't Neutrons bind Neutrons, with clumps of neutrons whizzing about? And, I'm guessing this is related: Why is a Neutron unstable outside its nucleus with about a 10.3 minute half-life?

Why does in QM the electron does not fall toward the nucleus? After all, the only force between nucleus and electron is attractive. It seems that the electron can and does indeed fall toward the center in <simple harmonic oscillator>? My question is what's so different in these two systems...

I have a question related to that is explained on the textbook Sedra & Smith. for a pole at s=a+bj,say, 1/(s-a-bj) why can we have the time domain of the signal to be exp(at+jbt)? It is strange because s=jw, so Re(s)=0 <a ,which leads to the solution to be -exp(-at-bjt)u(-t), so that...

I wasn't sure if I should post this in homework help or here, since it qualifies as both, so if this is in the wrong section, let me know and I will delete and repost it accordingly. Anyway... The instructions are (verbatim): "show that the given system is almost linear near the origin and...

Homework Statement Go through the arithmetic to verify that diamond becomes more stable than graphite at approximately 15 kbar How can diamond ever be more stable than graphite, when it has less entropy Homework Equations The Attempt at a Solution (dG/dP)=V, T and N are fixed. dP=15 kbar...

Homework Statement Nitrogen trifluoride, NF3, is relatively stable toward decomposition to its elements. In contrast, NCl3 can be dangerous to work with because of its tendency to decompose to N2 + Cl2, Use bond energies to rationalize. Homework Equations Bond energies for N-F is 278...

I want a MATLAB code to draw the root locus for a characteristic equation of a transfer function of unity feedback, also what is the range of K that keeps the system stable , here is the characteristic equation: s^5+600s^4+50000s^3+ks^2+24ks+80k=0 please help, thanks in previous

Homework Statement This is the autonomous differential equation: x" - 2x' + 37x = 0 Solve the above DEQ and state whether the critical point (0,0) is stable, unstable, or semi-stable. Homework Equations Solution to the above DEQ is x = c1excos6x + c2exsin6x The Attempt at a...

Hi! I'm a maths student taking a maths by computer course and this week's homework deals with the kapitsa pendulum (reversed pendulum). Homework Statement Kapitsa Pendulum is a rigid-rod pendulum the suspension point of which is vibrated. It turns out that vibration can stabilize the...

The recently announced $275B http://www.whitehouse.gov/blog/09/02/18/9-million-plus/#TB_inline?height=220&width=370&inlineId=tb_external" states that it intends only to reach 'millions of responsible home owners'. Indeed, Press Sec. Gibbs said today that the bailout is for ''those who have...

Homework Statement Hi all. I am given by following linear system: \begin{array}{l} \dot x = dx/dt = ax \\ \dot y = dy/dt = - y \\ \end{array} The eigenvalue of the matrix of this system determines the stability of the fixpoint (0,0): A=\left( {\begin{array}{*{20}c} a & 0 \\...

The problem and my work is below...I believe I got the problem to work out. The only question I had was if I found the LEAST moment of inertia which is what's needed for the formula at the end of my calculations. What exactly is meant by the least moment of inertia...

Im working on a problem involving a 70 lb empty drum. The diameter and length are given. I am trying to find if it will float stably if placed upright in water. I did a similar problem to this involving a solid cylinder with no problem. But I am trying to figure what special...

Hi, I am a student pursuing an MS in Aerospace Engineering with a concentration in Aerospace Structures. I am currently taking a course in Stability of Structures. The "required" textbook is Guide to Stability Design Criteria for Metal Structures (ISBN 0471127426), and the other recommended text...

I have a system transfer function H(s) = 1/(e^s + 10) This system has both poles and zeros at infinity and -infinity. Can anybody tell me if this is a stable system. Thanks.

Hello! Quick question, but it's really bugging me! Exergonic reactions often yield polar molecules as the products (e.g. combustion of methane). Are these polar molecules 'favourable' because the electrons are spending more time in a lower energy region; or is this wrong, and there's a...

I know some fine-tuning conditions which must be true in order for our universe, as we know it, to exist, for stars to shine and for the life to develop. For example, * CP violation (otherwise no matter because everything would annihilate) * Diproton (p+p) must be unstable (otherwise stars...

Homework Statement Determine the stability property of the following equibrilium solution: (0,0) of \ddot{x}+ \alpha x +x=0 with \alpha \in \mathbb{R} Homework Equations - A solution is Lyapunov stable if for each \epsilon there is a \delta such that: ||x(0)|| \leq \delta yields...

Does H2O2 stay stable once diluted in Water kept at 5-10 degrees. If so for how long?

Which one of these alkyl halides forms the most stable carbocation in a E1 reaction? Not II because it has an even number of delocalized electron pairs. Isn't I, IV and V the same?

Homework Statement How can i classify (1) stable node (2) saddle and (3) center as either (a) stable or asymptotically stable? Homework Equations <None> The Attempt at a Solution All three are stable. Stable node seems to be asymptotically stable. But I am not...

Homework Statement You are riding in a train and have just opened a bottle of beer. Prove that for your bottle to be as stable as possible on the table (which is shaking), you should drink sufficient beer such that the surface of the beer coincides with the centre of gravity of the...

1) As far as i think i understand, stability of a polynomial means; the polynomial correspond to a (its inverse laplace transform) differential equation, and the differential equations solution is dependant on the coefficiants of this polynomial? if the polynomial is unstable the solution of...

Hi, I have a choice of taking this advanced ODE course, and I am wondering if this is worth studying. The course will cover mainly chapter 9 of Boyce/DiPrima textbook after we cover existence and uniqueness theorem. Chapter 9 is called "Nonlinear Differential Equations", and covers topics...

Homework Statement Predict the stability order of dihalocarbenes. Homework Equations The Attempt at a Solution I'm lost. Just give me a hint and I'll see if I can get it figured out.

Homework Statement Why does the stability of highest oxiation state decreases from group 13 to group 17? Ans: My book says, that with the increase in atomic number, difference in energies between ns and np orbitals increases. Is it right? If so then can u please explain what relation...

GYROSCOPIC stability? So I'm reading about gyroscopes and how they can be used for stabilization of boats, yachts,etc. Most of these devices have a spin axis, and one or two gimbal axis. I am slowly understanding how the angular momentum of a flywheel and the precession create a counter...

It seemed to me that the elder bush, late in his term, started an intervention in africa that bill clinton would need to deal with. last week it dawned on me that the current bush might start a war with iran that obama would have to deal with. it seems that republicans intentionally start...

Hi there First of all excuse my English. My question is: Why a nucleus with more neutrons than these in the valley of nuclear stability are not stable and are beta(-)? I know that a nucleus with high mass number have more neutrons than protons because the more the protons the...

I've been doing some analysis on isotope data for a paper, and I've obtained some results which don't seem to appear in the literature. Have you come actross this? Here's the first one.

2 quick ochem questions... 1. Why is a carbon oxygen double bond more thermodynamically stable than a carbon oxygen single bond? 2. Can -OH be a leaving group in basic conditions, it would seem strange to protinate it in basic conditions? Thanks!

Dear all, I am a new member of this forum. I saw it many and I found it very interesting. I am solving a 2d transport equation. I discretized it in space with an upwind scheme and in time with Backward Euler difference. Hence, if I want to solve the problem I have to solve a linear system of...

Hi, just curious because I don't have it in my notes, say for fixed A (Atomic Number) we have Z_s which is the proton number that gives max stability. For Z =/= Z_s there are 3 1st order weak process that occur, does anyone know what these are? And when Z is far from Z_s there are two strong...

Dear subscribers Re: Stability test of reference electrode One of the important properties of reference electrode is its stability during measurements or potential scan. How one can check its stability in a certain electrochemical system? One of the way is to use internal reference...

I think that the most important thing we get in return from EU is that Europeans finally stopped beating each other up. Peace and stability, for the first time since the Roman Empire. The per capita gain of that is beyond all bookkeeping.

to those experts in the field of cosmology i was wondering if " large scale structures can be formed in stable cosmological models" or should i say that " large scale structures cannot be formed in those cosmological models that are stable with respect to gravitational or other curvature...