Stable Definition and 294 Threads

How do we prove that tetrahedral arrangement is the arrangement which allows 4 points to be maximum apart from each other about a fixed centre, assuming that the points are all symmetrical about the centre. (I am asking in context of the structures of the molecules like CH4, since there the...

From what I understand, there are some industries in Mechanical Engineering that are typically boom/bust (like oil and gas and aerospace). I wonder which ones are the most stable? I think HVAC is a possibility, but I don't know if it's the kind of thing that I would like to work on for my entire...

I want to build a Self Balancing autonomous bicycle for which I need to know about CMG System,Can Any one please guide me to the basics of Gyroscope and CMG- Ebooks would be a great starts.

Hello everyone, If a nucleus consisting solely of mesons has enough mesons in it, will it be stable? Mesons are bosons, therefore (unlike baryons) they aren't effected by the pauli exclusion principle, so they all can acquire the lowest energy state. In theory, if there are enough mesons, the...

Does more neutrons in an isotope make it more or less stable? I got two contradicting sources. I am also quite confused overall about the whole isotope business. The definition of an isotope is that it is an atom with the same number of protons but different number of neutrons. For example...

Hello! (Wave) Let a particle be forced to move over the sphere $x^2+y^2+z^2=1$, that is subject to gravitational forces while also to an additional "dynamic" $V(x,y,z)=x+y$. Find the stable equilibrium points , if they exist.I have found a similar example: Let $\vec{F}$ be the gravity field...

Hi, everyone! I saw this on Phys.org and thought it was interesting. Any comments?

Hi, my name is Andreas, and I am new to this forum. I had a couple of questions regarding orbital dynamics, since I am not very familiar with the field: Is tangential velocity in elliptical orbits stable like in circular orbits? If not, how exactly does it change? How do you calculate orbital...

Homework Statement Homework EquationsThe Attempt at a Solution For the above modeled transfer function of the plant, I'm trying to design a compensator that satisfies some requirements. a. The maximum control bandwidth (0 dB crossover frequency) is 100 rad/s. b. The minimum phase...

Homework Statement I am making a physics engine for my computer science class and couldn't figure out how to get the spring/mass system to come to equilibrium into a box-like shape such as the one on the left. I can understand why the one on the right is in equilibrium but I don't know how to...

Do more unstable elements decay faster than more stable ones? Thanks!

Consider a stable circular orbit (with a central force) subjected to small perturbations. The orbit equation is given by (3.45). The text argues that the ##\beta## in (3.46) must be a constant over the domain of ##r_0##: "Otherwise, since ##\beta## can take on only discrete rational values (for...

Homework Statement I want to find conditions over A,B,C,D to observe a stable limit cycle in the following system: \frac{dx}{dt} = x \; (A-B y) \hspace{1cm} \frac{dy}{dt} = -y \; (C-D x) Homework Equations Setting dx/dt=0 and dy/dt=0 you can find that (C/D , A/B) is a fixpoint. The Attempt...

I was wondering, since gravitational atttraction is determinated by m1 * m2 / d2 * G , can an object have a mass too little to have a stable orbit, for instance, around the sun? P.S: I'm new to this forum! Hello!

What are the prerequisites for learning 'Stable Domination and Independence in Algebraically Closed Valued Fields (ACVFs)' ?

The top and Higgs mass determination arose the old discussion about electroweak vacuum metastablity. There is an interesting fact that with available data the universe places in the edge of stable and meta-stable zone tends to be inside the meta-stable region. This conclusion confirms up to...

Hello everyone, When I look at the isotope lists, I always see only one nuclear spin for a specific isotope. (Why) can't an isotope have different nuclear spin types that are stable? I know metastable isotopes exist, but I am asking about the stable isotopes. Can't there be a case where the...

Hello! I've been trying to figure out what the most stable structure of inositol is, but I keep running into conflicting information. I'm not sure whether the most stable conformation is the myo-inositol form or the scyllo-inositol. All of the stereoisomers can be seen on wikipedia at this link...

Is the probability of an unstable atom becoming stable known and vice verse; is the probability of an unstable atom not becoming stable known? In other words if there were a thousands unstable atoms, how many of these unstable particles would become stable? Thank you very much for your help!

Here's the question: The CN molecule has been observed spectroscopically in comets where pressure has been estimated to be as low as 10–10 mm Hg. Draw a Lewis structure for CN. Suggest an explanation as to why this species can persist in a comet but is unstable under normal terrestrial...

Why the kink (\phi(x)=tanh(\frac{x}{\xi})), can not tunnel into vacuum +v or -v (Spontaneous symmetry breaking vacuum). From the boundary condition(x\rightarrow \pm\infty, \phi(x)\rightarrow \pm v), it is self-evident. but the book states: Due to the infinite high energy barrier, the kink...

As per control theory, if a bounded input produces a bounded output then a system can be said to be stable. So assuming that I press my cars gas pedal such that it reaches a fixed position, then the reaction of my car would be to reach a corresponding velocity, and assuming the road to be even...

The question is in the title: is it possible for a theory to be both UV and IR stable? And concrete models would be much appreciated!

Hi, I would like to get some help from you physics experts to solve this problem I am facing in my backyard. Here is the swing I have created using a hanging chair tied to a 23 feet high branch with a 1/4" aircraft cable made of steel strands. Problem: When the chair is empty it stays in one...

Homework Statement A homogeneous wooden bar of length 10 cm, thickness 4 cm and weight 1 Kg is balanced on the top of a semicircular cylinder of radius R as shown below. Calculate the minimum radius of the semicircular cylinder if the wooden bar is at stable...

I am going to hold a lecture on aerodynamics for a group of high school students, after which a competition on constructing the best glider is held. I think the planes will be made of sheets of balsa wood, and they are therefore likely to have flat wings. To help them succeed, I plan on telling...

Homework Statement This is a problem I picked for my calculus one class that I would like to solve, then model the solution using the sandbox video game universe sandbox. I would like to calculate the closest stable orbit of the moon, if possible allowing for some eccentricity in the orbit...

Hey! :o Which of the following sorting algorithms are (or can be implemented as) stable: Insertion Sort, Merge Sort, Heap Sort, Quicksort ?? How can we determine it?? (Wondering)

Hi Guys, I am new to this forum and interested in physics/Maths. Need your help with one of the problem I am trying to solve. The problem: Someone needs to build a 51 feet tall pole (usual shape of long lamp posts, thick at the bottom and thin at the top). but they want to make this pole such...

The basic "nuclear physics for dummies" explanation of nuclear physics goes something like this: There are two dominant forces at play in atomic nuclei: the residual strong force (aka the nuclear force) which binds nucleons together and the electromagnetic force (or, more simply, the...

Hey, I've a short question. Is there any research attempting to constrain models of dark matter by assuming stable solution for the universe? I'm interested in knowing whether this gives any sensible constraints on the dark matter models. I'm still fairly new to studying dark matter but as I...

Lanthanides can exhibit 2,4 states also but why 3 is most stable one?

Homework Statement Knowing the Z (number of protons) of an element, how can I find N (number of neutrons) or A (mass number) of the element? Homework Equations I tried to use the semi-empirical mass formula EB = ανΑ - αsA2/3 - αcZ2/A1/3 - αΑ(Α-2Ζ)2/Α - δ(Α,Ζ) for this. The Attempt at a...

Homework Statement A particle of mass 3m is located 1.00 m from a particle of mass m. You put a third mass M so that the net gravitational force on M due to the two masses is exactly zero. Is the equilibrium of M at this point stable or unstable for points along the line passing through M and...

It is theorem of any course on signals that a linear time invariant system, whether in discrete or continuous time, is BIBO stable if and only if its impulse response is summable. The fact that summability implies BIBO stability is easy to prove. In fact, it's on the wikipedia page of BIBO...

How can be sure than the unique stable particles are the neutrons, the electrons, the photons and the neutrinos? Couln´t it be possible than at low energies were there more particles??

Some book account for the reason that two vacuum points cann't be the same, how I understand it more easily?

A simple answer I got searching the web to as why we can't split atoms of non-radioactive elements is that they are stable.So,why can't we make stable elements unstable(radioactive)? Is this possible at least in theory?

DNA survives critical entry into Earth's atmosphere http://www.sciencedaily.com/releases/2014/11/141126144150.htm Full published article: http://www.plosone.org/article/fetchObject.action?uri=info%3Adoi%2F10.1371%2Fjournal.pone.0112979&representation=PDF

Greetings, I am interested in creating a thread dedicated to the discussion of the uses of currently discovered and used and theorized/dreamed of types of matter in our universe. This includes R.E.E's (Rare Earth elements, like Neodymium or Yttrium...

Homework Statement A solid hemisphere with radius b has its flat surface glued to a horizontal table. Another solid hemisphere with radius a rests on top of the hemisphere of radius b so that the curved surfaces in contact. The surfaces of hemispheres are rough, meaning no slipping occurs...

Hey guys, Im in the middle of a project and need help with the base for it. I have to develop a base for a rectangle 3 feet high by 2 feet wide by 6 inches deep. The front of the rectangle is 1 pound heavier than the back and will stand 2 feet off the ground. The base must be able to make the...

If a system is in a stable equilibrium state,its energy is maximum for fixed value of entropy ,the parameters and the amounts of constituents.Im wondering why this is true?Homework EquationsThe Attempt at a Solution

I understand it when you have a mechanism and the tertiary carbocation is more stable than a secondary and primary carbocation, but is that the reason? Cis-isomers are less stable than trans isomers because of steric strain on that side of the double bond, but a tetrasubstituted alkene will have...

Homework Statement Let a particle of mass m moving in 2d space in a potential V (x, y) = -1/2 kx2 + 1/2 λ0 x2y2 + 1/4λ1x where k,λ0,λ1 > 0.At what point (x0, y0) is the particle in stable equilibrium? 2 marks Homework Equations ∂V/∂x=0 ∂V/∂y=0; ∂2V/∂x2 > 0;∂2V/ ∂y2 > 0 The...

Why aren't positive and negative charges attracted to each other?

Homework Statement An empty cylindrical beaker of mass 100g, radius 30mm and negligible wall thickness, has its centre of gravity 100mm above its base. To what depth should it be filled with water so as to make it as stable as possible? Homework Equations Center of mass equations...

I want to output a specific wavelength of infrared light, I believe the wavelength was 9.25nm, how hard would that be and how would I proceed?

I have a question regarding the design of rocket nozzles. I am not an engineer nor a physicist but I am involved in amateur experimental rocketry and I was curious regarding grossly overexpanded nozzles. According to Wikipedia a grossly overexpanded rocket nozzle (very bottom of the...

I have no idea how activation energy of a chemical reaction (in either direction) could depend on the thermodynamic stability of formed carbocation, as a product of that reaction. Activation energy of a chemical reaction should depend only on the structure of reagents, right? The only thing...