Formation Definition and 508 Threads

1. Can anyone please explain in detail How a Vortex if formed. I mean what are the reasons and physical phenomena that cause the water entering a bath tub sink to gain a CIRCULAR ROTATIONAL motion and form a Vortex. How do the water molecules otherwise traveling straight towards the sink...

its being said, " more the loss of energy, more the strength of the covalent bond" revered members, could u explain why? thanks in advance

I understand the measurement process is sometimes divided into 1) a "premeasurement" which consists in the formation of correlations between system and apparatus (entanglement) and.. 2) a choice between the different eigenvectors of the observable's operator. I would like to understand...

Hi! I've been trying to find explanations about the theoretical formation of naked singularities, and all I could come up with was Wikipedia, and frankly, the explanation didn't "set" in my mind, I couldn't really visualize it. It reads: "From concepts drawn of rotating black holes, it is...

Hello, Having a spot of bother here trying to understand the glass formation in metallic glasses. Could anyone please explain or point me to a source that explains in details structure and kinetics in glass formation? Thanks

And if we increased the size of our imaginary planet, how massive and large could it get before it undergoes fusion? Also, I'm pretty sure you could never actually get a Uranium planet, but is there enough to have Uranium asteroids in a star system, or at least asteroids that are radioactive...

Hi, I am in my second year at Sixth Form College and I have chosen to do Crater Formation for my second year physics coursework. I took some readings and found that a lighter ball makes a deeper crater than a ball of the same diameter but greater mass. I don't know why this is. I would expect...

Hi Not sure of optical questions should go here to general physics questions, but here goes. I have a doubt, basically, what consists of a reflection? If i have a perfectly smooth surface, then the specular highlights are infinitely thin, and you should have perfectly mirror-like...

I was reading something about formation of black hole, and it was given that exclusion principle has a role in BH (Black Hole) formation. It read "when star become small, the matter particle get very near each other, and so acc. to Pauli's Exclusion principle they must have different...

Hello - I'm having some problems understanding Gibbs energy of formation, and how it's applied to electrolysis. So, I'm hoping someone can explain what I'm doing wrong.. According to his site: http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/electrol.html (image) The change in the Gibbs...

Homework Statement Sorry if this kind of question is atypical for this forum. I'm trying to understand the physical concepts involved in my chemistry class. My homework is covering lattice enthalpy, and to get the lattice enthalpy of an ionic compound using the Born-Haber Cycle...

Hi All, I´m quite new to physics (from a biology background) and am hoping someone can give me a quick explanation of what causes the Earth to have a magnetic field. I have read about the dynamo theory but am finding it difficult to visualise or is it as simple as moving currents make an...

band gap arises due to lattice potential.band gap is produced at zone boundary due to bragg reflection.there it behaves like standing wave instead of traveling wave?further formation of 2 standing waves?please help

Homework Statement Please help! i just need to see one step by step solution of how to solve this problem and then I can figure the rest out. When .560g of Na (s) reacts with excess F2(g) to form NaF(s), 13.8 kj of heat is evolved at standard state conditions. What is the standard enthalpy...

I'm currently writing a computer simulation (in Java) of the formation of a helix from a spinning thread. The analogy I use is to imagine a piece of thread held between two fingers and left to hang via gravity. When the thread is spun by rolling one finger against the other, the thread will...

I'm currently writing a computer simulation (in Java) of the formation of a helix from a spinning thread. The analogy I use is to imagine a piece of thread held between two fingers and left to hang via gravity. When the thread is spun by rolling one finger against the other, the thread will...

Homework Statement Three positive point charges are arranged in a triangular pattern in a plane, as shown below. The Coulomb constant is 8.98755 × 109 N · m2/C2. Find the magnitude of the net electric force on the 2 nC charge. Answer in units of N. Homework Equations Fe = (kq1q2) / (d2)...

No, this is not about whether or not Farrah has an STD. I don't know whether this belongs in Physics or Engineering, so feel free to move it. In a normal day, I have a need to apply one drop of water at a time to something. A drip rate of anywhere from 1/2 second to about 3 seconds is...

Homework Statement For the reaction A-->2B+C, the following data are obtained for [A] as a function of time: t=0min, [A]=0.80M; 8min, 0.60M; 24min, 0.35M; 40min, 0.20M. Calculate the rate of formation of B at t= 28 min. The Attempt at a Solution I have found out that this equation is a first...

Understanding the first star formation is critical to cosmology. Matt Turk is a (remarkably young) expert on this. The way they go about it is with computer simulations and checking the results against whatever can be observed. Here is a talk by Matt Turk...

Homework Statement What is the formation of an amide Label all reactants and products Homework Equations O ll The Attempt at a Solution R-C-NH2

For a gas and dust cloud to collapse under gravity to form a star and planets, is the concept of friction important at all? In other words: let's consider a large number of billiard balls, no internal degrees of freedom, participating in completely elastic collisions, with random initial...

I am reading some theoretical papers on the defects in semiconductors. Theorists can calculate the formation energy of a certain kind of defect. If the number is too big, this defect is very unlikely to be seen. So what does this “formation energy” mean? Is that the energy necessary to move...

Hello! Homework Statement If a chemical is used to inhibit spindle formation, what phases would you not see [under a microscope]? 2. Possible answers Prophase Prometaphase Metaphase Anaphase Telophase The Attempt at a Solution I figured prometaphase, metaphase and anaphase. I know...

Homework Statement A tank of water has been outdoors in cold weather, and a slab of ice 5 cm thick has formed on its surface. The air above the ice is -10C. Calculate the rate of ice formation ( in cm / h) on the ice slab. Take the thermal conductivity of ice to be 0.004 cal / (s.cm.C) and...

I am not very versed in physics but if it was possible to collide antimatter with antimatter would that create a black hole?

According to the History Channel documentary Comets -- Prophets of Doom (DVD), Earth today accumulates "30 to 40 thousand tons of space dust per year". CRUDE MODEL: We imagine that the accumulation rate of space debris declines exponentially: rate = T \times e^{-\frac{t}{\tau}} We then...

I have for a long time now wondered about how the planets and moons actually congealed into their current forms. How can loose mass and gas develop the gravity to pull themselves together? Could the cause of these actions been related from the "big bang" which threw out micro black holes of...

How does the temperature of a star relate to the radius of a star? How does the mass of a star affect the temperature of the star's core? How does the luminosity of a star relate to how long a star will live? How do the spectral lines of a star determine if the star is a first generation...

hi there.. is there anyone know how to synthesis an Acetylsalicylic Acid from Acetic Anhydride and Salicylic Acid . i just know how 1 step.. but then my proff told me there's suppose to be like 5 or six step to obtain it. i'll appreciate your response.

Hi everyone! My first post, so bear with me. I have a query that I didn't quite know who to ask about, and came across this site, so I hope this is the right place to put it. My cat's bowl was left (empty) on the verandah and got caught in the rain yesterday afternoon. Overnight...

Homework Statement The problem statement is to find the heat of formation of NH4CL using the calculated variables and two more reactions. If I calculated it correctly the HF for ammonia plus hydrochloric acid to be -247.7kj/mol. I am not sure what else it is that I need to do...

[9] arXiv:0809.2330 [pdf, other] Title: Hydrodynamics of structure formation in the early Universe Authors: C. H. Gibson (UCSD), T. M. Nieuwenhuizen (University of Amsterdam), R. E Schild (Harvard) Comments: 6 pages 4 figures. Additional information at this http URL Subjects...

This paper makes the case for an upper mass limit of about 10 billion solar, for black holes. Their central black holes may help galaxies to form and may be important to understanding structure formation---an outstanding problem in cosmology. The mass limit is proposed tentatively and requires...

Structure formation is arguably the central problem in cosmology. How did the dilute gas manage to coagulate. On what timetable did stars and galaxies form? What explains the distribution of galaxy sizes and composition--clustering--the wispy cobwebby structure with its various size voids...

http://blackholes.stardate.org/resources/articles/article.php?id=9 This presupposes that dark matter and dark energy interactions play no role?

When things are kept at the simplest, I've heard that galaxies were formed because gravity pulls stuff together, but there's some things that are not fully making sense. If two objects are far away, and they get attracted by gravity, what happens is that they merely pass each others with some...

http://space.newscientist.com/article/dn14435-universes-first-stars-bulk-up-in-new-simulation.html The new computer simulation study suggests that early stars tended to be quite large, order of 100 solar masses, implying short life. The possibility is mentioned that the James Webb telescope...

Hi folks, I've recently been studying point defects, but I can't seem to come across how the formation of f-centres actually affects the density of a crystal. Does it increase or decrease the density? Thanks for any help/ ponters

I think this question was addressed many times in the literature but I was not able to make a clear picture for an answer. It is known that peculiar velocities of galaxies are too small to explain the formation of voids. Voids must have existed already before galaxies were in place with their...

When our star the Sun finally accumulated enough matter for fusion to start what would that have done to the planets around it? Afterward what would have happened to the Earth for it to get from when the sun started fusion and blasted the Earth and now, with water and atmosphere?

Homework Statement I'm interested to know how cooper pairs are formed in low temperature superconductors. The Attempt at a Solution My basic understanding is that electrons will repel other electrons and attract the positive ions which make up the lattice of the metal. The attraction...

1. An object is placed in front of a converging lens in such a position that the lens (f = 11.0 cm) creates a real image located 27.0 cm from the lens. Then, with the object remaining in place, the lens is replaced with another converging lens (f = 19.0 cm). A new, real image is formed. What is...

Homework Statement The diagrams below illustrate the formation of a rainbow. Figure 1 shows the general arrangement and Figure 2 shows the path of a ray through a raindrop with the centre of the raindrop is labelled O. Figure 1: Figure 2: a.) Where the ray enters the raindrop in...

Homework Statement This is a question from a sample exam that I can't figure out. The answer is 1297 kJ/mol, but I don't know how to solve it. Any help is appreciated. ----- The following are average bond energies (kJ/mol): C−H 413 O−H 463 C=C 614 C−C 348 O−O 146 C=O 799...

[Sorry about the long post] I'm doing an essay where I am exploring whether or not elements were, for the most part, formed under conditions of thermodynamic equilibrium. We know that some element clearly aren't (such as Potassium 40 and uranium which decay radioactivly). I've scoured the web...

[SOLVED] free energy of formation Homework Statement Consider the reaction 2NH3(g) --> N2(g) + 3H2(g) If the standard molar free energy of formation of NH3(g) at 298 K is –16.45 kJ·mol–1, calculate the equilibrium constant for this reaction at 298 K. The correct answer is 1.71E-6...

Homework Statement This is not a problem, per se, because it is part of my Lab. We're calculating the standard enthalpy change of formation for solid Ammonium Chloride. To do this, we're using four separate rxns, and totaling their individual standard enthalpy change of formations. For two...

Acetanilide synthesis HCl, aniline, sodium acetate trihydrate=> Acetanilide I'm being told that there is an intermediate formed (anilinium hydrochloride) but I can't figure out how it is formed exactly. (Is the reaction, for the anilinium hydrochloride just the aniline attacking a H-Cl...

Has anyone had experience with calculating the enthalpy of formation from DFT? I have had a few calculations with the planewave-pseudopotential method. What puzzles me is that in one case the agreement with experimental values is excellent, while another case was about 30% more stable...