Energies Definition and 299 Threads

Career in alternative energies engineering... I have a BS in Mechanical Enineering with several years experience with general ME practices (i.e CAD design of parts and systems, CAM and machine work, project management). I am looking to start a carrer in alternative energy engineering. I am not...

Homework Statement Initially, a 10 kg block is sliding along the floor at a speed of 5 m/x. The coefficient of friction between the block and the floor is 0.5. What are the KE, PE and total energies of the block after sliding 2.0 m? What is the block's speed after sliding 2.0 m? I...

The succesive ionization energies in kj/mol of an element x found in period 3 of the periodic table are: 1800,3000,3600,5800,13200. With the aid of a periodic table,what is element x?

What do the phenomenologists of unified theories (strings, loops etc) try to match at lower energies when there are so many conflicting theories lying around at these energies? I understand that certain things should be there in any model - like chiral matter, three generations etc - but a lot...

just a question about the energies associted wuth the schrodinger equation> are the energy values always positive values. I thought that since when the eigenfunctions exist the particle is in a bound state, that the energy should be less than that required to escape a bound state and should be...

I have to find the kenetic energy lost in the problem. I have both initial and final kenetic energy, how do i calculate the percent loss? I tried final over initial times 100 but that is not correct.

This question is not a homework question. I am having a little trouble with the ionization energy graph. I understand that the noble gasses are the most stable and hence require the most energy to be ionised, but why is it that after you add even number of electrons the ionization energy...

Homework Statement So the question asks me to find the energies of the 2nd, 3rd, 4th, and 5th excited states in a three dimensional cubical box and to state which are degenerate. Homework Equations -\frac{\hbar^{2}}{2m}\nabla^{2}\Psi + V\Psi = E\Psi The Attempt at a Solution so I...

Homework Statement A hydrogen atom is in the n=6 state. a) Counting all possible paths, how many different photon energies can be emitted if the atom ends up in the ground state? b) Suppose only\Deltan=1 transitions were allowed. How many different photon energies would be emitted...

Homework Statement What is the calculated binding energy of the electron in the ground state of (a) deuterium, (b) He^{+} and (c) Be^{+++}? Homework Equations For the hydrogen atom, E_{n} = - E_{o} / n^{2} E_{o} = me^{4} / 2hbar^2(4\piEo)^2 The Attempt at a Solution Not sure...

Homework Statement A simple pendulum has a length equal to 0.6 m and has a bob that has a mass equal to 0.5 kg. The energy of this oscillator is quantized, and the allowed values of energy are given by En = (n + 1/2)hf0, where n is an integer and f0 is the frequency of the pendulum. Find n...

Homework Statement I got ask the following question, and i don't know the answer. Why in a rdioactive decay of 232Th by alpha emission, the alpha particle can have energy 4.01 Mev and 3.95 Mev? Homework Equations The Attempt at a Solution I look up this website and i found...

Hi, first time poster. Quick question: Why is the bond energy for a bond that contains a more highly substituted (tertiary) carbon weaker than the bond energy of a bond that contains a less substituted (primary) carbon? Let me clarify with an example. Say Bond A is a single bond between a...

Hi guys... I have a small question on potential energies: I have got two potential energies: \begin{equation} U_1=-\frac{k^2}{2}+\frac{w\sqrt{3}}{2}\sin^2\theta \cos 2 \phi \end{equation} and \begin{equation} U_2==-\frac{k^2}{2}+\frac{w\sqrt{3}}{2}\sin^2\theta \sin 2 \phi...

Homework Statement i) Explain why in alpha decay short half lives correspond to large disintegration energies. ii) Determine the energy release during the alpha decay of 238U to 234Th. The mass of 238U is 238.0508mu, the mass of 234Th is 234.0436mu, and the mass of 4He is 4.0026mu...

Homework Statement a wrecking ball, with a mass of 315kg, hangs from a crane on 10.0m of cable. if the crane swings the wrecking ball so that the angle that the cable makes with the vertical is 30', what is the potential energy of the wrecking ball in relation to its lowest position? What will...

Not sure if this should go here or in the relativity forum... let me know if I need to move it. I was reading something, and it said this: "A photon also has a rest mass, which is zero, even though a photon is always moving at the speed of light, and so is never at rest. But if an observer...

Where in quantum field theory does it say that probing something at high energies is equivalent to probing it at small distances? Most of the time things are done in momentum space (such as the Feynman rules) so we have no clue about distances and location. The only time I even remember using...

Homework Statement Prepare a table of spectral lines by color, with correct wavelengths, and corresponding energies for every line spectrum you observed. Pick one line spectrum and explain the order of color from least to most energeticHomework Equations I'm not quite sure what to do here. I...

I have to graph changes in energies. And I have a question - so I have a battery that supplies power to a motor and some sensors. I have to assume it starts with 36000J of energy (chemical energy, right?). Then, pretend a motor uses 22J and shuts off. Now I would have 35978J of chemical left...

Hello, I'd like to ask a question about the electron binding energies of oxygen atom. As is known, when an oxygen atom gains one additional electron to form an anion with charge -1 it gives some 1.4ev, while it gives nearly 7.8ev if two additional electrons are bound to it. Considering that the...

Homework Statement Suppose that a positron traveling at a speed of 0.93c collides head on with an electron traveling at the same speed. What is the sum of the energies of the two photons? Homework Equations mass of an electron = 9e-31 kg E=\gammamc2 - mc2 The Attempt at a...

1. The problem statement, all variables and given known data Hi all. Lets I have a system, whose Hamiltonian is given by H = p_1 + p_2, where pi is the momentum of i, where this i can be whatever, e.g. momentum in some particular direction. When the Hamiltonian is given on this form, do I know...

Homework Statement The masses of the javelin, discus, and shot are 1.0 kg, 2.0 kg, and 8.0 kg, respectively, and record throws in the corresponding track events are about 98 m, 75 m, and 25 m, respectively. Neglecting air resistance, (a) calculate the minimum initial kinetic energies...

What regulates the ground state energy of a hydrogen atom? Why is it constant (more or less)?

Homework Statement Consider the box potential V (x) = 0 0 < x < a 1 elsewhere a) Estimate the energies of the ground state as well as those of the First and second excited states for i) an electron enclosed in a box of size a = 10E-10 m. Express your answer in...

Homework Statement Two bullets have masses of 4.7 g and 11 g, respectively. Each is fired with a speed of 39.0 m/s. a) What is the kinetic energy of the first bullet? Answer in units of J. b) What is the kinetic energy of the second bullet? Answer in units of J. c) What is the ratio K2/K1 of...

Homework Statement What are the energies of the ground state and the first two excited states of the He+ ion? Homework Equations En= - Eo/n2 The Attempt at a Solution n=1 for this problem (since there is only 1 electron) so the ground state would have the electron...

Compton scattering and the energies of incident and scattered photons...? [b]Hey guys! I'm alittle stuck...Hope you can shed light on this for me! The question is: 'In a head-on compton encounter, the total energy (i.e the rest mass plus the kinetic energy) of the scattered electron is...

So I was doing physics homework today, and wound up spending a couple hours on wikipedia, browsing through topics far out of my league- particularly nuclear physics. I'm left with an aching question that I hope someone here can help me out with. In a nuclear reaction that requires a certain...

Hi guys, I hope you can give me any idea about: After a long molecular dynamic simulation of a polymer under periodic boundary conditions, dihedral and total energies are lower than zero, (negative). do you know the physical meaning of that result? thanks for reading and for your help...

I'm reconsidering the problem of resonance states. We know that the resonances in QM are described as the complex energy poles in the scattering amplitude. In the version of QFT, the resonances are described by the complex mass poles of the scattering matrix. In QFT, I can understand that...

i have two questions... does an electron have a continuous range of energies? I think the answer is no. am i right? and also... what does the solution of the schrodinger's equation provide?

"Consider an infinitely sharp pin of mass M and height H perfectly balanced on its tip. Assume that the mass of the pin is all at the ball on the top of the pin. Classically, we expect the pin to remain in this state forever. Quantum mechanics, however, predicts that the pin will fall over...

Homework Statement A photon of initial energy .1 MeV undergoes Compton scattering at an angle of 60degrees. Find: The energy of the scattered photon The recoil energy of the electron the recoil angle of the electronHomework Equations \Delta\lambda= (h/mc)(1-cos\theta)The Attempt at a Solution

I cannot see how the two can be mutually inclusive. If you super impose particles with potential energies that fall off as 1/r that are homogeneously distributed through space then take the gradient of them, I hardly believe that they will result in the exactly the same thing than if you take...

Just a quickie. For example, the total kinetic energy of N molecules is = (3/2)NkT = (3/2)nRT If a question were to ask you to find the such energy for a sample of N_{2} would it make the equation (5/2)kT? Does the subscript 2 make it diatomic, and hence have two molecules, I am not sure...

Hi: In experimental HEP, Why are higher energies associated with shorter distances , and by the way, in order to reach higher energies or shorter distances, an increase in the size of the detectors is needed, Could you please tell me why?. For instance Why do we meed a particle...

Homework Statement A lambda hyperon \Lambda^{0} (mass = 1115.7 MeV/c^2) at rest in the lab frame decays into a neutron n (mass = 939.6 MeV/c^2) and a pion \pi^{0}: \Lambda^{0} \rightarrow n + \pi^{0} What are the kinetic energies (in the lab frame) of the neutron and pion after the decay...

Homework Statement A positron has the same mass as an electron but is of opposite sign (9e-31 kg). What is the sum of the energies of the two photons which are produced when the positron and the electron annihilate? Assume the speed of the positron is .93c (c is the speed of light) with an...

Hi. I'm trying to calculate the adsorption energies at all high symmetry sites on an Aluminium (111) surface (consisting of a few atomic layers). The adsorbates are hydrogen atoms. I make sure that one hydrogen atom per primitive surface cell is adsorbed (i.e. one monolayer of hydrogen atoms...

Homework Statement For a particle moving in a potential V(x), what are plausible forms of V(x) that give: (i) entirely continuous, (ii)entirely quantised (iii) both continuous and quantised energies of the particle? Sketch, with justification, the forms of V(x) for each of...

Hi, I'm starting a prac on muon lifetimes and we have been asked to calculate the range of energies suitable for the experiment... Thinking about this, I was a bit stumped as to what we were supposed to be calculating... Is this a limitation of the detection equipment? Or do low energy...

Does anyone know how to construct a Time-independent wave function with given energies and probability on obtaining energies.

Hi everyone... I hope this is the right place to post. Anyway, I am a first year grad student working on molecular dynamics simulations (with very little background in materials, yay) of iron. To start out, I'm just trying to replicate some materials constants with a basic lattice to make...

Homework Statement Use the bond energies (in Table 4.2) to calculate the energy changes associated with each of these reactions. In each case indicate whether the overall reaction is endothermic or exothermic. Be sure to show your calculation work. [b]2. Homework Equations [/b The...

Just joined so I hope I'm in the right place: My Question: I read that in the creation of a water molecules, a pair of hydrogen molecules break apart releasing 4.53 evolts of energy. Why does the hydrogen spectrum show binding energies of -13.6, -3.4 ,-1.511, -.85, -.544 but not 4.53 or...

I have this problem to solve, but I can't seem to find the right formula. It says to use "an expression for energies of a Bohr atom in a weak magnetic field". I've looked in my coursebook but I can't find anything useful. Can anyone help me?

Homework Statement The overall activation energy E is 60 kcal/mol. Reaction steps are: CH3CHO --> .5CH3CO + .5CH3 + .5H2 E1 = 80 kcal/mol CH3CO --> CH3 + CO E2 = ? CH3 + CH3CHO --> CH4 + CH3CO E3 = 10 kcal/mol CH3 + CH3CO --> minor products...

Is it possible in principle to accelerate particles to arbitrarily high energies? Suppose technology is no bar and there is sufficient money to build accelerators. Can we accelerate particles beyond say Planck energy? or is there is some limit? For example from special relativity we know that to...