Energy Definition and 999 Threads

Hello, I am trying to correctly interpret the energy diagram below. For example, a diatomic molecule can translate (kinetic energy), rotate (rotational energy), vibrate (vibrational energy). Each different type of energy is quantized and has associated modes (also called states). The...

Hi, To compute, for example, the Gibbs energy change for a ligand binding to a protein, various so called alchemical methods are used in molecular dynamics simulations. My question is why can't we just obtain averaged Gibbs energies for 1) the free ligand and protein in the same water box, and...

I honeslty don't quite know how to start. It seems like the Hooke's coefficent k is independent of the answer to this problem. I would also appreciate any clue of expressing the condition when "balls will collide again". The fact that all balls can keep moving make this rather difficult. It...

Hello, In thermodynamics, with systems being represented by gases (can liquids be also included?), the internal energy ##E_{int}## of a system represents the total kinetic energy + the total potential energy of the system: $$E_{int} = KE_{tot}+ PE_{tot}$$ The term ##KE_{tot}=Q## is also called...

In the frame of the accelerated block, I applied the non-inertial force F'. My doubt is if I can conserve the mechanical energy in the accelerated frame and find the speed at the top. Otherwise, how could you proceed.

Hi, I'm curious about the ultraviolet catastrophe, and how Planck decided to hypothesize the quantization of energy integrally proportional to frequency to explain the drop off of energy in the higher frequencies. So what I don't understand is, when the energy is transmitted as a photon, does...

Many of you would have heard about physical energy levels. Like maintaining the physical energy throughout the day so that you do not get tired. People recommend exercising, meditating etc etc. But I found out that my mental energy drains at a very rapid rate. I wake up with full energy but...

I'm looking at Schutz 7.4 where first he obtains the following expression for a geodesic: $$ m \frac {dp_\beta} {d\tau} = \frac 1 2 g_{\nu\alpha,\beta } p^\nu p^\alpha $$ This means that if all the components of ##g_{\nu\alpha }## are constant for a given ##\beta##, then ##p_\beta## is also...

a) So far, I have equated Ek to Eg to solve for h. 1/2(m)(27)^2 = m(9.8)h. I haven't taken the angle into consideration. I'm not sure if I have to use the x or y component. I got my answer to be 37m but again I don't believe this is correct. b) I did Ek = Eg + Ek. 1/2(m)(27)^2 = m(9.8)(3.5) +...

Hello. I have a question about the law of energy conservation in GR. As time is inhmogeneous, we don't have energy-momentum 4-vector which would be preserved during system's dynamical change. It is only possible to define 4-vector locally. And next, the problem regarding how to sum this vectors...

Hi, When regarding Gravitational Potential Energy, I know the formula is U=mgh. However, when the object is on an incline (say at an angle of 52 degrees) would it still be mgh or something else? (This isn't homework I simply was just curious).

I am interested in energy flux density from the Moon at Earth’s surface, specifically in infrared (albeit most of it comes in infrared anyway). Physics.SX (boyfarrell) gives an estimate 89 mW/m². I doubt it for several reasons. 400 K (as effective mean) on Moon seems to be unrealistically hot...

The wave function or Schroedinger equation is timeless, correct? You can reverse the equations and forward it. Our arrow of time comes due to decoherence in macroscopic object. How about energy bands in solid state. Do you consider it as timeless wave function, or is it decohered?

Table: To solve, using the conservation of energy: E0=(m(deutron)+m(16O)-m(17O)-m(p))c^2 so: E0=(2.014+15.994-16.999-1.008)931.5=0.93 MeV. so using the conservation of energy: 14.95+0.93=16.62+0+E' E'=- 0.74 MeV But the energy sign has become negative. I also calculated for the first excited...

First to compute the time derivative of ##\mathcal{E}##,$$\mathcal{E}_t= \phi_t \phi_{tt} + c^2 (\nabla \phi_t) \cdot (\nabla \phi) + m^2 c^4 \phi \phi_t = \phi_t \left[ \phi_{tt} m^2 c^4 + \phi \right] + c^2 (\nabla \phi_t) \cdot (\nabla \phi)$$Then we switch out ##\phi_{tt} + m^2 c^4 \phi##...

Hi! Hope I'm posting this in the right place! I'm practicing for exams and came over this question: A proton with mass ##m_p## is accelerated to a relativistic velocity, with kinetic energy ##K##. It collides completely inelastic with another proton, which has the same kinetic energy, ##K##...

Like an electric field is applying a sort of force on a particle. I was wondering if this at all impacts the potential energy of a particle. For instance, when the force of gravity does work on an object, its potential energy changes as a consequence. Would it be the same thing here?

I am given the answer is 2J and I know how to get there with U = q^2/2C. But what I don't understand is that why is the energy not conserved here? How can energy loses just because the capacitance is doubled?

I think I have a rough idea about it, but I am not sure whether it is correct. At least I feel that my understanding is a bit vague. Here it is: Globally (I mean across all worlds), the energy is conserved because the universal wavefunction evolves strictly according to Schrodinger equation...

So Ekf-Eki+Epf-Epi=0. I understand that the final potential energy is 0 (distance away approaches infinity), but don't get why the final kinetic energy becomes 0. If the final kinetic energy was 0, wouldn't that mean the object no longer has any velocity and would start being effected by the...

Hi, my question is that what is the main challenge of high energy physics? what is the best theory that maybe explain it and why it would not be accepted?

E= 3/2 (1.381x10^-23)(4x10^8)(2x10^19)50 E= 8.29 x 10^6 Wrong

Hello there, I have a question regarding this problem. I have no problem with part A. However, in part B, my solution manual states that the hollow cylinder will reach the bottom last. Why is it? I mean shouldn't the solid cylinder and the hollow one reach the bottom at the same time? you know...

I have used the heat equation and am not able to get the initial heat. This is what I have so far: 81060 = 7 * 140 * (change in temp) - (7 * 11300) + 7 * 140 ( change in temp) I found the change in temp to be 81.71K. But that does not help me with the initial temperature!

I have often read that dark matter and dark energy are now thought to comprise 94% of the total mass of the Universe. Just now I was reading an article which says that dark energy comprises 74% of the total. So, I'm confused about how energy can comprise mass. Dark matter, I can understand -...

I understand that the mass is being converted to energy but isn't it just an destructive interference of the properties of particles being present as waves of possibility , for example when electron is Interference with it self is it produce energy?, because the particle are weaves in quantum...

I don't really know how to proceed. Can someone help me out in this?

I want to know the difference between potential and potential energy. The potential is measured in volts and we provide potential ex 12V to a circuit. Some times we also say a potential energy to be applied to the electron ex. 1eV etc. I know eV is energy, but my question is do we need to...

m1v1+m2v2=m1vs'+m2v2' , if car hits small fluffy object m2, initially v2=0, and v1'=v2' ... so m1v1=[m1+m2](v2') but why not energy? Why is there a KElost? .5m1v1^2+.5m2v2^2=.5m1v1'^2+.5m2v'2^2 +KElost , and again v2=0, v1'=v2' .5m1v1^2=.5[m1+m2]v2'^2+KElost using consv of momentum...

I was just reading about the LIGO experiment wherein an interferometer was used to detect gravity waves. This interferometer uses opposed light waves, detecting if there is a shift in their wavelength due to stretching/squeezing of a gravity wave passing through the lasers. (I hope I'm saying...

Hello, Trivial question: a system is isolated and all its internal forces are conservative. Because of Newton's 3rd law, all internal forces are pairwise and the net internal force is always zero (regardless of the forces being conservative or not) hence the system's total momentum is conserved...

Hi!.. As known, a certain amount of energy is applied for compressing a mechanical spring. Thus mechanical spring is charged with energy and it stores it as elastic-potential energy. But whole energy, applied for compressing spring, can not be converted into potential energy. The reason is...

Hi Pf I read that in the light propagator there are loops of electrons. What would be the consequences if we could switch them off (or neglect them)? would it modify the speed of the photons?

Can you reverse entropy without using energy?

the answer in the solution book is 29K which only comes if I use mass for only one atom. ( They did not show any working ) My attempt: 1/2 x (1.67 x 10^(-27)) x (355)^(2) = 3/2 x 1.38 x 10^(-23) x T T = 29.48820652 K The confusion arises when I tried the following question: Q. Estimate the...

as I read here http://www.bbc.com/earth/story/20160429-the-real-reasons-nothing-can-ever-go-faster-than-light#:~:text=But%20light%20is%20made%20up,when%20particles%20like%20electrons%20cannot%3F&text=The%20natural%20energy%20they%20possess,are%20already%20at%20top%20speed. things with mass...

Summary:: Calculate the amount of energy in joules generated from 2 kg of uranium fuel if the uranium 235 represents 0.7% of the metal and every fission releases 200 MeV. Hi! I am stuck in this question from my exercise book : Q. Calculate the amount of energy in joules generated from 2 kg...

Hi, Planck's equation is written as E=hν where "E" is energy of a photon, "h" is Planck's constant having value 6.626 070 15 x 10-34 Js, and "ν", Greek letter nu, is frequency. Violet color has frequency range between 790–666 THz (Tera =10^12). If a violet photon of frequency 7.5 x 10^14 Hz...

I don't need the whole answer just a few tips to do it. I think it's something with the two different radiuses, but I'm really bad at this. We did a similar one in class, but there is a trick in this one that I can't figure out.

I am learning about capillary action of water. As water moves up paper. How is that not violating energy conservation as it is going against the force of gravity. This obviously can't be infinite energy.

So what I did first was calculate the initial and final potential energies with Epi=-9.433*10^11 m and Epf = -1.503*10^12 m. Then I found change in potential energy, -5.597*10^11 m. Using this I determined the change in kinetic energy, 5.597*10^11. I then added this change to the initial...

Hello, I would like to review and validate some concepts that I have been recently thinking about. Hope this is correct and useful to others that need to refresh these concepts. Forces can be classified as either conservative or nonconservative. Dissipative forces are always nonconservative...

I tried using U=3/2 NKbT, but i don't seem to get the correct answer..

Good day everyone, I've recently been researching direct energy conversion schemes for nuclear fission, and I have a question on the basic physics behind the device (specifically on how it converts kinetic energy to electricity). In essence, the "basic" scheme for fission DEC devices is that...

I know I'm probably overcomplicating this question, but I'm having a bit of difficulty coming up with a singular answer. I have a 4-foot diameter flywheel that I need to turn with an electric motor of an unknown horsepower. I say unknown because I I don't know what I need based upon the...

First, it is easy to see that n=4 after the collision because: E_1=-13.6\frac{1^2}{1^2}eV=-13.6eV E_4=-13.6\frac{1^2}{4^2}eV=-0.85eV E_5=-13.6\frac{z^2}{5^2}eV=-0.544eVBut, I never saw a definition for the width of an energy level. I tried to use something I saw online that said it was...

(a) Using COE, $$mgh = 0.5mv^2 + 0.5I\omega^2$$ I solved it, where $$\omega = 112 rad/s$$ (b) This is the part where I have question or problem. I saw my course mate working and he start of with finding centripetal acceleration. $$a_c = \frac{v^2}{r} = \frac{(r_0\omega)^2}{R_0}$$ Why isn't it...

$$R_{eff} = R_1 + \frac{1}{\frac{1}{R_2}+\frac{1}{R_3}} = 1.4 + 0.6 = 2$$ PD of R3 = 4 / 2 * 0.6 = 1.2 Net PD of the capacitor = 2- 1.2 = 0.8V $$ E = \frac {1}{2} CV^2$$ E = 0.8 ^2 * ( 3*10^-6) / 2 E = 9.6 * 10^-7 Correct answer is: 4.27 * 10^-7 was thinking if i should find the Effective...

1. If today vacuum and matter contribute 71 % and 29 % to the total energy density of the universe, at what redshift z were they contributing equally? 2. If today vacuum, matter, and radiation contribute 71 %, 29 %, and 0.01% to the total energy density of the universe, at what redshift z were...