Stable Definition and 294 Threads

not asking about neutron stars, where gravity holds neutrons together, rather would the strong force hold individual neutrons together in a solid mass, preventing their decay if one could somehow put them together in a lab?

I am struggling with Hamiltonian formulation of classical mechanics. I think I have grasped the idea of canonical transformations, including the idea of angle-action variables and invariant tori in phase space. Still, few points seem to elude my understanding... Let's talk about a particle...

V = ? m/s V = D/T V = Square root (6.67 * 10^-11)(m)/r

I was wondering if we could have an object made up of only electrons. Normally, that wouldn't be possible because electrons repel each other. However, this repulsion can be overcome using gravity. So my question is, how many electrons would you need to have their gravitational attraction...

Say one was to create an artificial stable isotope of Promethium as it has predicted applicable properties. What would it’s number have to be? I know Promethium-147 is semi-stable.

Hi all , please refer to the picture regarding my working. please correct me if My working is wrong. I am quite confused about the positive and negative sign in equation

As an example specifically, sputtering is used for putting coatings onto razor blades. People are told to not wipe the blade for cleaning. So does the coating have any resistance like in case a user gives a single pull through something like a cork or a styrofoam cup, to remove any accumulated...

Hi, All cosmological models with a non-zero cosmological constant will approach a de Sitter universe in the far future. In theory this can means that the most basic group of particle physics should be the de Sitter rather than Poincaré. Mass is a Casmir operator of the Poincare but not of the...

I wonder if you could help me with both I'm stuck, I know that in order to see if the electrostatic equilibrium is stable or not at the center of the ring , the potential energy has to be minimum there. I was going to use Laplace eq. but it allows neither minimum nor maximum. Then I also...

Summary says it all, I think. If you just want to link me to a bunch of papers, that's fine by me. All I was able to find out on my own is that mouser and digikey have a lot of off-the-shelf voltage references they want to sell me that get about order of ##10^4## SNR at those timescales. SNR...

Homework Statement:: The solution to the KG equation is assumed to take the form$$\Phi = \sum_{l=0}^{\infty} \sum_{m=-l}^{l} \frac{1}{r} \phi_{lm}(t,r) Y_{lm}(\theta, \phi)$$ Relevant Equations:: N/A To first show that $$\left[ \frac{\partial^2}{\partial t^2} - \frac{d^2}{dr_*^2} +...

I need to create a 5 V stable DC supply out of 6 V AC from a transformer. By "stable", I mean that I do not want the ripples in the voltage that one gets from the output of a full-wave bridge rectifier. I have to feed this to two ATmega 8A μCs. I am going to create the following circuit: 6 V...

Just quick question: Could you put space stations (or even other small planets) at any aribitrary orbit or any radius in between Jupiter and Mars? Or, if something attempted to do so, would the orbit be unstable, and the object drift to either Mars or Jupiter? I was reading about Lagrange...

Hey everyone! So I have attempted this Q which is shown below I had a go at all the parts and I think they are right but I'm not so sure on what answer to give for c)iii, I mentioned about the ratio of protons to neutrons but I'm not sure if that is necessary over here? Any help would be...

Hi, I am reading the following paper: Toward Practical Secure Stable Matching: https://encrypto.de/papers/RSSSK17.pdf. According to the paper: and at other place: Somebody please provide me an example for this model i.e reducing from multiparty data into 2-party data. Zulfi.

I was discussing a problem related to Einstein's universe model. As we all know its an unstable equilibrium. So a small fluctuation in the density would result in an either expanding or contracting universe. However, I read that "There are static and stable solutions in Newtonian gravity...

In Thailand university professors become an unstable job due to a new policy. There's literally zero job security even if you get tenured (become associate ,assistant profs) you'll still get sacked by the authorities if you don't conform to them. Little to No retirement pensions. Some professors...

Is it possible to have a configuration of two classical positive charges and two classical negative charges that will remain fairly stable (or at least metastable), if started off in some well-chosen initial condition? For example, we might want to eliminate radiation by having the electrons...

I tried by taking the derivative of the potential to find the critic points and the I took the second derivative to find which of those points are minimum points. I found that the point is ##x=- a##. I don't understand how to calculate the period, since I haven't seen anything about the harmonic...

Why is Uranium-236 less stable than Uranium-235 and Uranium-238?

Homework Statement A) By examining the effective potential energy find the radius at which a planet with angular momentum L can orbit the sun in a circular orbit with fixed r (I have done this already) B) Show that the orbit is stable in the sense that a small radial nudge will cause only...

Homework Statement y(t) = x(1-5t) Homework Equations noneThe Attempt at a Solution well I've never looked at the stability of a signal which has a time scale and shift. My guess is that it is stable as anything I can provide as input will output a bounded signal. Ex: if x(t) is u(t) then...

I´ve seen it asserted at the general physics forum that melting point of amorphous substance is "always" lower than the "melting point" of corresponding crystal. Also, amorphous solids are often described as metastable against crystallization. Does it necessarily apply to all amorphous solids...

I recently learned that Bismuth is actually radioactive with its longest lived isotope having a half-life of about 20 quintillion years. (For source, see: https://www.nature.com/articles/nature01541) As a very basic question, what determines whether an element/isotope will be radioactive? Is...

Homework Statement [/B] Which is more stable cyclobutane or cycloheptane? Homework Equations [/B] [(n-2)180)]/n = angle The Attempt at a Solution [/B] So the closer the angle is to 109.5 the more stable (except for cyclopentane vs cyclohexane). n = number of carbons [(7-2)180)]/7 = 128.57...

Imagine a steel I-girder lifted by a single wire rope. If the rope is not perfectly centered along the girder length, the girder will rotate about a horizontal latitudinal axis through its centroid. Imagine a girder pair lifted by two wire ropes, with one rope on each side of the girder...

What's the difference between neutral and stable? As an example of H2. Here two H atoms combine and make an H2 molecule. Now two H atoms are neutral as they have the same number of protons and electrons. So the H2 molecule is neutral. on the other hand. Two H atoms combine through a covalent...

Homework Statement A circular hoop of radius R rotates with angular frequency ω about a vertical axis coincident with its diameter. A bead of mass m slides frictionlessly under gravity on the hoop. Let θ be the bead’s angular position relative to the vertical (so that θ = 0 corresponds to the...

Hello Everybody! My name is TanX and I got a figure in my mind while studting concepts related to Vertical Circular Motion. I tried finding a solution to it (i.e) I tried finding the condition for movement of the particle in the figure that had come in my mind... Homework Statement So here is...

I am in the process of writing a lecture out for my Graduate modeling class I teach. I normally don't write lectures out in LaTex or use PDF's because I write on the dry erase board, but if anyone is interested I wouldn't mind spending the time to type out some notes on the topic. The topic...

https://futurism.com/stable-plasma-ring-created-open-air-first-time-ever/

Homework Statement I'm having difficulty knowing how to determine if a given differential equation represents a stable, neutrally stable, or an unstable system. I was given a hint to focus on the homogeneous solution, so is the particular solution not important for determining if the...

Hello, I have been wondering if it is possible to create and store stable ions, is it? Thanks.

i really need help about shunt and series resistances i just want to know if they are constant or variable ? if they are variable what make them increase or decrease?

I was looking at this neat graph of all the isotopes and which ones are stable and how they decay: https://upload.wikimedia.org/wikipedia/commons/thumb/c/c4/Table_isotopes_en.svg/715px-Table_isotopes_en.svg.png The black squares represent stable isotopes, and columns that have no such black...

Does GR allow for photons to be in a stable orbit around a massive body?

Hi there. I was trying to solve the time dependent diffusion equation in only one dimension. I derived a explicit scheme using a finite difference in the time variable. The equation I am trying to solve is: ##\displaystyle \frac{1}{c} \frac{\partial \phi(x,t)}{\partial t} -...

in a universe without the higgs field fermions would be massless in absence of the higgs field, would second and third generation fermions such as muon tau top quarks etc be stable? how to distinguish between a massless electron muon and a tau in a universe without the higgs field, same for...

Homework Statement The controller K(s) = Kp, determine the range of Kp over which the closed loop system is stable. Homework Equations I found the transfer function of system = Y(s)/V(s)=Kp/(1.5s^2 + 2.5s - 1 + Kp) The Attempt at a Solution So i know (1.5s^2 + 2.5s - 1 + Kp) is the...

Hi, I'm not a scientist or engineer,, I'm actually an artist, with severely insufficient knowledge in chemistry . I also don't work for a big company that's funding my project, I'm paying for everything myself. I trying to make a water in oil micro-emulsion at home that does no require any...

Homework Statement [/B] Give examples of fixed points of vector fields and maps that are stable in the linear approximation but are nonlinearly unstable Homework EquationsThe Attempt at a Solution [/B] I was able to find an example in a vector field that, when the Jacobian is found and the...

Homework Statement http://i.imgur.com/Jt3u2uo.png Homework Equations octet structure bond strength bond order The Attempt at a Solution I have no idea why the answer is b... after reading the book... thank you.

The N body problem has no closed solution, and in many cases closely spaced bodies around a major body kick members out. In our solar system we have Titus Bode relationships that space orbiting bodies out in a geometric series. Various resonances are common. In Trapp1st 1, the planets are...

Homework Statement Using the Semi-empirical Mass Formula show that for fixed odd atomic mass number, A, the most stable isobar has a neutron to proton ratio given by N/Z = 1 + aCA2/3/(2aA) Homework Equations B(A,Z) = aV A − aS A2/3 − aCZ2A-1/3 − aA(Z − N)2/A + pairing term The Attempt at a...

I have a doubt, that in astable multivibrator how do we place the transistor bc107 in opposite side on a breadboard? If anyone know please show me in a demonstrated post.

Hi everyone, I have created a simulation of the major bodies in the Solar System, using the exact positions, velocities, and masses etc. at midnight on Jan 10 (as provided by the NASA HORIZONS project). Using Newtonian gravity I numerically simulate the forces between all the bodies (with a...

why uranium does not have any stable isotope?

I understand that in a 2-body system a circular orbit is gravitationally stable in General Relativity. In Newtonian dynamics, an elliptical orbit is also stable, but is this also true in GR? I understand that the orbit precesses, but I do not intend that to change my meaning regarding stability...

I am really interested in physics, and have a knack for it (am currently in my second year of physics at college, so I think I can honestly match myself up with other physics majors), but am not a savant or anything. I would love to push through and finish the degree, but the degree doesn't seem...

Homework Statement Why is the EA of Neon endothermic even though it has a high Z eff? Basically, what makes a full valence shell so stable? The attempt at a solution I know it has to do with shielding, core e-, and valence e-. But I don't know how to word it.