Energy Definition and 999 Threads

Discussion with people related to energy and work on the field of finding new energy source, Article and research paper based on source of energy, Videos related to future energy source.

Can someone explain to me what the second integral represents and what is A?

By exciting hydrogen vapors with heat or electrical discharges, it is possible to obtain the element's emission spectrum. In it, as can be seen, appear multiple wavelengths, each corresponding to a particular orbital electronic transition. From this it can, therefore, be inferred that heat and...

I ran across the following problem : Statement: Consider a gas of ## N ## fermions and suppose that each energy level ## \varepsilon_n## has a multiplicity of ## g_n = (n+1)^2 ##. What is the Fermi energy and the average energy of this gas when ## N \rightarrow \infty## ? My attempt: The...

Problem: Attempt at solution: So "energy passing through per unit area per unit time" is equal to $$I = \frac{E_i}{A t}$$ So for a the graph will be in the form of ##y=1/x##? For b) do we have to solve the differential equation $$dI = \frac{E_i}{A dt}$$?

Our Governator is attending the Austria world initiative on climate change. He wants us to know that we have "2000 Gigabytes of clean energy" waiting to be developed if only the permit process can be expedited. Lucky us. Listen to the video at about t = 2:20 and rejoice...

Position and momentum are the popular pairs of properties with uncertainty we often hear about, for example that we cannot know with precision where an electron is and its momentum at the same time. What are others? Such as an example of an energy and a time that we cannot know both...

Hi, Am i correct in thinking that if we take a block of ice, moving at a constant velocity, it's then exposed to a heat source which melts the ice and turns it into water vapour, that we have simply removed any Kinetic energy, by Sublimation or converting it into heat. My question is does the...

Hi Everyone! I am an upperclassmen undergrad of a biol background, with mainly course training in biochemistry and molecular biol, and taken chem like o-chem and a-chem, and introductory physics. I have three short term summer projects at top 5 institutions in the past and in the field of...

Answer: The energy of a system with H and Cl atoms at varying distances can be represented by a curve that shows the potential energy of the system as a function of the distance between the two atoms. At very large distances, the potential energy is zero because there is no interaction between...

For this, From the work kinetic energy theorem, if we assume that the book and the earth is the system, and that the finial and inital speed of the system is zero, then is the work KE theorem there is no net work done on the system. However, clearly there is work done on the system is shown by...

I initially tried to solve this equation using work, but was stuck in a confusing integral that didn't make sense. I am almost sure that the utilization of energy is needed to solve this equation, but I have been flustered for the past three days at solving this.

Given that there is a cylinder rolling without slipping down an incline, the method I was taught to represent the KE of the cylinder was: ##KE_{total} = KE_{translational} + KE_{rotational}## ##KE_{total} = \frac {1} {2} mv_{cm}^2 + \frac1 2 I \omega^2## Where "cm" is the center of mass, and...

I do private studies on my own for fun and right now I read about relativistic field theory as a preparation for later studies of quantum field theory. I simply do not understand where equation 13.78 in Goldstein's "Classical Mechanics" third edition comes from. Please explain. Please also...

So, I cannot for the life of me write a conservation of energy statement, when an object is lifted up by a force. So in my example there is a box on the floor with v = 0, and then a force of magnitude F, where F > mg, acts on the ball, now the net force is F-mg, and hence the work done is (F -...

Usually, I like to take a physical approach to phenomena that occur in everyday life. But I feel difficult to solve problems because I don't have higher education My question stems from this question (What's the difference between running up a hill and running up an inclined treadmill?), which...

Here's an applied everyday life physics question based on a MVA (motor-vehicle accident) I was involved in a few weeks ago. I was driving straight when a women hit me from the driver side (said she didn't see me due to being in her blind spot - her claim, not mine, as I don't know if I was or...

I've already solved the orbital speed by equating the kinetic and potential energy in the circle orbit case. $$\frac{1}{2}mv^2 = \frac{1}{2}ka^2.$$And so $$v^2 = \frac{k}{m}a^2$$Now when the impulse is added, the particle will obviously change course. If we set our reference point in time just...

mgh=(1/2)(m)(v^2) gh=(1/2)v^2 sqrt(2gh)=v Should have the same v, but this is not the case based on the answer and real-life experiments.

The starting point is the identity $$\left(\frac{\partial u}{\partial T}\right)_n = T\left(\frac{\partial s}{\partial T}\right)_n.$$ I then try to proceed as follows: Integrating both with respect to ##T## after dividing through by ##T##, we find $$ \int_0^T \left(\frac{\partial s}{\partial...

I need the theoretical energy density of inflation for my story. I seem to recall it as an enormous 1095 ergs per cubic centimeter.

Not a solution. This is the graph provided. I think I start with finding the magnitude of the IF vector but I’m not sure. And I don’t know where to go from there.

This is actually a two-part question: 1) According to the Copenhagen Interpretation, atoms have energy bands but there's no explanation of how these bands are derived, or why they only form for protons/antiprotons. Any thoughts? 2) The Copenhagen Interpretation mentions that when an atom's...

Hello, is someone able to explain why these two are wrong. I am not sure how to figure out the enthalpy direction as the reaction is not changing state of matter, nor is it changing temperature. (Please solve without calculating anything) Thank you

Knowing that negative work occurs when the force applied to an object opposes the direction of displacement, and that the direction of acceleration vector should align with the force vector, I assumed the correct answer was that the indication of negative work comes from negative acceleration...

Hey all, On page 446 in Peskin, he provides 2 different ways of writing the Gibbs Free Energy: $$\textbf{G}(M,t) = M^{1+\delta}h(tM^{-1/\beta})$$, and $$\textbf{G}(M,t) = t^{\beta(1+\delta)}f(Mt^{-\beta})$$ where ##h## and ##f## are some initial condition functions that have a smooth limit as...

Since the system is doing no work, would it be just 4513 J? I don't think there is any other information to use

Hello. Could someone please help me with this question about bond energy from an MIT course: "For two bonded atoms X and Y, a small X and large Y will result in a bond energy (E A-B) with a large __________ contribution." Thanks a lot if someone can help.

Griffith's E&M problem 4.7 asks to calculate the energy of a dipole in a uniform electric field and I ended up getting a different answer than the one given. I thought that calculating the energy/work done to construct the dipole is the same as dragging two point charges where one is d apart...

Is it possible that in combustion, the chemical energy of reaction is released wholly through photon emission. Say as in simple burning of wood.

In Avengers: Infinity Wars Thanos had the Infinity Gauntlet and when he snapped his fingers it wiped out 50% of life in the universe. Roughly, how much energy do you think the snap generated assuming the universe IS finite in size (since an infinite universe cannot have any percentage) AND the...

The cylinder in question would have a moment of inertia of ~1.67kg*m² and rotational KE of 2.058J. At the point of impact also, assuming the body hits the sphere at a 90deg angle after traversing 90deg of displacement, it should(?) exert a force of 1.31N - enough to give an acceleration of...

Question: With maximum do they mean that the speed of the pions is the same as the proton and an antiproton? Otherwise there will be two unknowns, and if I use both relativistic-energy and momentum conservation equations I get difficult equations.

Is there a way to independently determine the proportion of dark energy density to total energy density of the universe apart from using 1 -(Ωmatter+Ωdark matter )?

Hello everybody, I consider two electrons that have enough kinetic energy to reach their respective classical electron radius. This would be: 2.0514016772310431402e-13 J The corresponding speed is v = 287336682 m/s. The electric field is E = \frac{k_{e}}{R_e^2} = 1.8133774657059088443 ×...

A) I just did what it said to do: $$\sin\left(4x_{1}\right)=1\implies x_{1}=\frac{\arcsin\left(1\right)}{4}\ m=\frac{\pi}{8}\ m\approx 0.392699081699\ m$$ B) I modified the method from an example from the lecture the other week: $$U\left(x\right)=-\int...

First, "Energy is not conserved" as e.g. explained by Sean Carroll in https://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/ . Second, the Friedmann Equations are expressed in energy conservation, e.g. https://core.ac.uk/download/pdf/25318877.pdf equation (16). Do we...

Starting to explore quantum mechanics, I read strong nuclear force that binds protons and neutron together in nucleus of atom, gives atom its mass. More binding energy means more mass of atom. Hence the query that, for example there are two magnets having a force F1. And we have the same size...

My attempted solution is as follows: Obviously the heat transfer happens during transitions 1->2 and 3->1. It's also clear that P1 = P3 V1 = V2 E2 - E1 = Integral[T dQ , from state 1 to state 2] E3 - E2 = - Integral[P dV , from state 2 to state 3] E1 - E3 = Integral[T dQ , from state 3 to...

Is it a total energy of a vibrating molecule? So is it a sum of potential and kinetic energy? Or it is only a total energy of a vibrational motion of the molecule? Or is it only a potencial energy, when it is related to a dissociation curve? I am confused.

For this problem, How can energy be conserved if the bit highlighted in orange is true?Many thanks!

Hello, I've seen in a few books on solid state physics that one can deduce an expression for average K.E.: $$<\:K.E.>\:=E_c+3/2\:k_B\:T$$ from the following: $$<\:K.E.>\:=\:\frac{\int \:\left(E-E_c\right)g\left(E\right)f\left(E\right)dE}{\int \:g\left(E\right)f\left(E\right)dE}$$ I can't...

Hi. I'm not sure where to put this question, thermodynamics or the quantum physics forum (or somewhere else). For a system in equillibrium with a heat bath at temperature T, the Boltzman distribution can be used. We have the probability of finding the system in state n is given by ##p_n =...

There is a celebrated energy equipartition theorem, it works fine for many systems. But it requires the dense filling of the surface of constant energy. What if there are other conserved quantities, like momentum or angular momentum? It seems, that the energy partitioning will be uneven, with...

Assuming dark energy is fairly, uniformly distributed through out the cosmos, how strong is it, or how much energy is associate with it, out in the deepest, emptiest voids in space? I'm specificlaly refering to the great voids in between the great walls of galaxy clusters. I'm making the...

I got answer for (a), which is 0.51 m For (b), loss of potential energy = 35 x 9.81 x 0.51 = 175 J Rate of loss of potential energy = 175 J / 1 s = 175 W But the answer key is 80 W. Where is my mistake? Thanks

I'm watching a video about " What is a black body?". That video said when the light interacts with the surface of a body, the electron and proton start oscillating. The electrons gain more transferred energy from the light that became its kinetic energy, rather than the proton because its mass...

I could not find any derivations in the litterature, except for the expected value of the energy flux expression itself: $$\overline{\Phi_{effusion,\epsilon}} = \overline{\dot{N_{ef}}}\overline{\epsilon_{ef}}=\frac{3Nl}{2A}\sqrt{\frac{(k_BT)^3}{2\pi m}}$$ I've started off by calculating the...

For example, if a ball is from a certain height, the work done is 0 as there is no change in total energy the Ef =Ei. However, there is a constant force applied over a certain distance, suggesting work is being done. Which aspect am I forgetting/missing? Or is it that the definition of work done...

So here's what I did but it isn't right: W = (Kf + Uf) - (Ki + Ui) (2.6)(9.81)(0.45)(-0.01)=(1/2mvf^2 + 1/2kxf^2) - (1/2mvi^2 + 1/2kxi^2) -0.1 = (1/2(2.6)(vf^2) + 1/2(855)(0.02^2)) - (1/2(855)(0.03^2)) 1.3Vf^2 = 0.114 Vf^2 = 0.09 Vf = 0.3 m/s