Stable Definition and 277 Threads

Because torque is force times distance, wouldn't it only take a relatively small force to make a rocket unstable if the force was applied near the base or the top? How is it kept stable? I just saw SpaceX's future plans to make a fully recyclable launch vehicle; I think it is far fetched TBH.

At the last scattering surface (LSS), the energy density of neutrinos is argued to be ~0.68 of the energy density of blackbody photons, based on a thermodynamic equilibrium argument. This is also required to obtain the correct total energy density for stable expansion. At that time, the average...

By "physical particle" I mean color-singlet particles which have asymptotic T=\pm \infty states. How many stable particles exist in the theory? Only one? SU(2), SU(3), and SU(N) gauge groups can all be discussed.

Laplace transform includes exp(-st) and s=σ+jω. σ is negative in the left side and hence exp(-st) goes to infinity. It is not stable. Where am I wrong?

Can some one give me ideas that how can we do above question.

Hello again. In the first fork in the road thread I outlined some problems that I am dealing with, and you kind folks offered many suggestions. The 3 big ones that I can remember without looking are: 1) Find roommate. 2) Join Military 3) Work multiple jobs and save up more money. I...

What all the parameters to be calculated to find a vertical standing beam subjected to axial loading stands without buckling or stands stable? My HW problem has a theoretical question, a vertical beam is fixed on both ends. Loaded on the top with axial load. Show that with an example...

Is stable nuclei decay? if no then how and why know please ans me i am waiting

Which one is more stable? I heard that Aerospace Engineers get hired for a job, then get fired. I'm going to be a junior in High School next year and I'm thinking about what I want to be. Thanks!

Hello! I don't know if this is in the right place or not. So if it's not, I won't misplace it in the future. Anyway, I was recently thinking about the orbits of planets around Binary Stars, and was wondering if it's possible to have a similar orbit around the Earth and the Moon. Have a...

Ok, so all elements undergo radioactive decay. But why? I have been snooping around and what i find is that radioactive decay occurs because of instability of the atom nucleus in quantity, proton-neutron ratio and energy content; therefore we have alpha, beta and gamma decay consecutively...

If a small black hole were to fall into a star or brown dwarf, presumably it would initiate accretion and fusion in a shell around it. Can such an object be stable over any decent timescale, or would it undergo variability/significant mass loss/supernova?

?How to know if equilibrium points are stable or not. Is my solution correct Homework Statement Homework Equations The Attempt at a Solution solution above

I know odd-odd nuclei are generally unstable against beta decay as the pairing term in the semi-empirical mass formula is less than zero, and I know even-even nuclei are generally stable, but I don't get the rules you apply for even-odd or odd-even nuclei. Do you have to work out the binding...

Would it seem reasonable that so-called ‘hot jupiters’ are in resonance i.e. have a stable orbit? If one utilized our stellar system as a simulation, with the addition of a hot jupiter, then what would the resonance be? Would it be calculated as non integral? Then if our cold gas giant were...

A one-dimensional force F(x)=(3.0N/sqrt(m))*sqrt(x)-(1.0N/m)x acts on an object of mass m = 2.57kg. a Find the position x0 where the mass is at a stable equilibrium. b Find the frequency of small oscillations around that equilibrium position. How does this compare to the frequency if we...

I have a object of mass m=5.34Kg. There is a force acting on the object F(x)=(5.0N/m[1][/2])*(x[1][/2])-(1.0N/m)*(x). 1)I need to find the position x0 where the mass is in a condition of stable equilibrium. 2)What is the frequency of oscillation around this position? How would this frequency...

The boiling point for R-ethyl 3-hyrdoxybutanoate is about 75 C The boiling point for S-ethyl 3-hyrdoxybutanoate is about 180 C How!? How is the same molecule that much more stable just by rearrangement of the hydroxy group. I'm trying to explain how some R enantiomer may boil off along with...

I am preparing for my control theory exam, but I have come across that I am struggling. I have a third order system and its asking to me determine when a value of an adjustable parameter, K for when the system is critically stable. I just don't know what this corresponds two for a third order...

I understand that Iron3+ has a half filled 3-d level, but I also know that in reality when one electron is lost from elemental iron, the lone pair from the 3-d level will move to the 4s level to stablelize it. What I really want to know is which ion is more abundant in nature? Thanks guys

Hi, What would it take to produce a stable black hole in a particle laboratory? Must one use some kind of focuser and shielder to prevent the initial point from evaporating? In some entanglement experiements, they use laser to remove the thermal agitations in the particles. Can we do the same...

If it didn't escape to space so easily, then would it easily react with other things on Earth's surface?

I was thinking that since the density of something is as much dependent on the molecular structure as the atomic, that there should be some leeway here.

Especially over geologically significant intervals of time? Is cave collapse inevitable?

Does anyone known this, or is this something that is not known. Where is the photon located before it is released? Is it located in the electron?

Hello. I have a function which doesn't work near A=0. I want to change it to something that a computer can evaluate for any value of A. y = [exp(Ax) - 1] / [exp(A)-1] As you can see below, it approaches y=x when A->0. I was wondering about multiplying the numerator and denominator by...

(1) Is there any equation to determine how many neutrons there should be to keep an atom stable? I don't mean mass - number of protons. I mean the equation that can determine an interval of neutrons based on atomic number only and the forces. (2)Why can't there be an hydrogen atom with 6...

I'm going to college next year and I am having a really hard time choosing what to do. I really love physics. It is my passion and I am really good at it. I want to major in physics, but I know getting a lucrative job in that area is not going to be easy. I have been poor my whole life and I...

Whenever I think of an ion I think of an atom that can generate electricity. Something powerful. I wonder, if an ionic state is a pretty rare state to be in that only happens under special, and mostly temporary conditions? Or, is my view of ions wrong?

I need help ranking the following from most stable to least stable: -(CH3)2C=CHCH2 with dot over the CH2 -(CH3)2CHCHCH3 with dot over the 2nd CH -(CH3)2CCH2CH3 with dot over the C -(CH3)2CHCH2CH2 with dot over the CH2 the dots represent the primary, secondary, and tertiary radicals...

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...

Homework Statement The system with impulse response h(t) = a_{1}\delta(t-t_{1}) + a_{2}\delta(t-t_{2}). Is this system stable or not?Homework Equations The Attempt at a Solution I drew the h(t) response and I got something like that: but I don't really know how to prove it. There is no input...

So mesons consist of two quark. I am wondering why no stable mesons exist?

What's makes an atom stable or unstable? From what I know, if an atom has a mass number Z that is more than 83, it is unstable and would undergo radioactive decay to make itself stable. So, is there any criteria that classify an atom unstable?

Aspiring hard-scifi writer here. I try to make sure details in my fiction are consistent with known science or reasonable extrapolations thereof, unless absolutely demanded by the plot (and even then I try to offer some justification). I'm wondering if the solar system I'm setting a short story...

Homework Statement This isn't really a homework question, but it is part of a lecture powerpoint that the teacher will go through with on Monday and I was just getting ahead so I can understand better. [PLAIN]http://img59.imageshack.us/img59/3088/cuelectronconfig.png Homework Equations...

What is marginal stable airplane?

I enjoy Physics like many and always keep an eye out for new discoveries, but is our understanding of the universe becoming too complicated and involved. We are constantly finding new information that does not fit the current model, but by adding a new constant or variable into the equations it...

Clearly, I need to look at the potential function and differentiate it to determine extreme and then the stability of the extrema. However, I'm not sure how to do this mathematically at the moment. http://i111.photobucket.com/albums/n149/camarolt4z28/2010-09-14203321.jpg?t=1284516380

So far I've read enough articles to believe that stranglets with a mass of greater than the equivalent of 1000 protons can be stable at ordinary tempertures and pressures. Assuming the strangelet is positively charged, there is no threat to normal matter due to coulumb effects. I've also...

I'm somewhat new here, so forgive me if I ask an inappropriate question (defined as too far out there; this is supposed to be a legitimate site). How could it be possible to make Nickel-78 stable, and still remain Nickel-78? Nickel-78 decays via Beta-minus decay, which means one of its...

Can there be any particle other than a proton or a neutron that can remain stably in the nucleus of an atom at ordinary temperatures and pressures? I'm aware of hypernuclei (nuclei containing hyperons) but none of those are stable. I understand that they all decay weakly. Is there any...

The equation for the surface gravity of a black hole in Kerr metric is- \kappa_\pm=\frac{r_\pm-r_\mp}{2(r_\pm^2+a^2)} where r+ is the outer event horizon- r_+=M+\sqrt(M^2-a^2), r- is the inner event horizon- r_-=M-\sqrt(M^2-a^2) and a is the spin parameter in metres- a=J/mc. An exact...

Is an electron the smallest stable subatomic particle? By stable I mean it can exist independently of other particles.

If you are in free fall inside a black hole, shouldn't it feel like normal space even though people on Earth saw you enter a black hole?

Curvature Cosmology is a cosmology based on two hypotheses. The first, curvature redshift, is an interaction between photons and curved spacetime and produces the observed Hubble redshift. It can also explain the anomalous Pioneer 10 acceleration. The second, curvature pressure, is a...

Hi, I'm in my last year of school and part of my A-Level is on nuclear physics. We've recently studied binding energy and I noticed that the elements with the highest binding energy per nucleon (the most stable nuclei) are magnetic - iron, cobalt and nickel. Are binding energy and magnetism...

Imagine a planet in elliptical orbit around a star, without any perturbation from third bodies and moving in perfect vacuum. The only force acting in the system is gravity. As the planet gets closer to the star, gravity acts in the direction of its motion, so it gains speed and KE but loses...

I plan on building shelving using 3/4" pipe and fittings. The general design is a 2 shelf system -180 degrees from each other around a center pole at different heights. I plan on bolting the center pole to a plywood base. Each shelf will hold between 5 and 100 lbs. I want to make sure its...

I just realized couple of days ago that I had never known why helicopters were stable, and avoided tipping over. When you look at a helicopter, it creates an intuitive impression that it is stable, because the center of mass is below the rotor. It seems as if it the helicopter's body is hanging...