Energy Definition and 999 Threads

Why is (1/2)(mv0)^2 = 1/2(M+m0)gh not a valid equation for conservation of energy? Isn't the energy from when the dart is shot the same as when the two masses move at speed v?

When E=mc^2 is rearranged using the substitution c=1/√ε0μ0 , and making mass the subject we get m=Eε0μ0 This equation basically says that mass is directly proportional to the energy contained in an electromagnetic field. Does it not? Does this equation tell us that mass particles are made up of...

Imagine an object, e.g throwing knife, spins in the air but not forced to rotate about a particular axis, i.e no rod impaling it and forcing it to spin about the rod. Then the axis of rotation converges to it's center of mass (CM) to minimize I. But there's nowhere for it's rotation energy to go...

Suppose in a different star system, a space shuttle sized spacecraft acquired a solar mass energy equivalent amount of kinetic energy, then passed through our solar system. While it was passing through the solar system would the craft’s gravitational effects be more similar to the space shuttle...

That question has been puzzling me recently. But I know there is a simple answer to it.

I've tried to solve this exercise but I haven't used one of the properties of the system (the displacement of the masses) so I don't know if I'm wrong about my procedure. First of all, we (obviously) know that $$ P=P $$ And since we can express the power of a force in two different ways, we...

So if we set the damping constant ##\beta=0## that is if we consider an undamped oscillator the amplitude becomes infinity! What is the physical meaning of this phenomena? As we know energy fed into the system is proportional to ##A^2##. So does this mean that an infinite amount of energy is...

Absolutely no clue on how to even begin this question due to the exceptionally poor quality of our lectures, who has also flatly refused to give out any solutions, which I could have used to understand what is going on. I assume the energy has to be obtained by using the eigenfunction equation...

Hello, I am wondering if anyone can give me a hand. I am looking for a unified expression for energy in rotating systems or wondering if one even exists. Any help or equations you wish to share about the topic would be great. Sorry I am quite new to physics. Thanks

Suppose I have a protein PDB file and want to compute energy using the following formula from the coordinates in that file. How can I do that? Sometimes people suggest using the `CONECT` field for that purpose. However, some PDB files do not have this field. Example: 4OSK.pdb (Crystal...

In a simple circuit consisting of a battery and a resistor, current will flow if the circuit is closed. Resistor uses the energy provided by the battery, creating heat with a power ##P = UI##, where ##U## is a voltage across the resistor and ##I## is a current through the resistor. In my...

I tried E =Fxcos0 but only ended up with 243kJ

I registered yesterday in this forum with the intention of someone clarifying me how the Heisenberg uncertainty principle can explain the existence of virtual particles. More energy implies less lifetime is only possible if ΔE Δt = h/4Pi, but that's not Heisenberg's principle, the principle is...

A Beta-Type Regular Low Temperature Striling Engine being used to produce mechanical energy, where hot water at 350K is being used as fuel. What power should one expect theoretically?

^^

I approach this by considering the four springs in parallel each with spring constant ##k## as one spring with four times the spring constant ##k' = 4k##. The car is dropped and at the moment its tyres touch the ground I assume that the spring is in its resting position. As the car continues to...

Theoretically possible, only if the process is reversible. But is it really. My knowledge base is insufficient to answer that. I need help.

In his Chapter 13.3 (2nd edition), Callen gives the standard form for the virial expansion for the mechanical equation of state of a fluid as an exapnsion in powers of the molar volume ##v##: $$P = \frac{RT}{v}\left(1 + \frac{B(T)}{v} + \frac{C(T)}{v^2} + \dots \right) \equiv P_{ideal} +...

I'm self-studying the mathematical aspects of quasi-local mass, or quasi-local energy (e.g. Hawking energy), and a fundamental question has been lingering in my mind for a long time: why does quasi-local mass provide us with a measure of the gravitational energy? In general relativity...

I converted 3.1eV into J, substituted into E = mc^2. Since the energy is the same, I got the same answer for both: 5.52*10^-36 kg. This doesn't seem quite right- I doubt that a photon and an electron have the same mass. So, when two particles have the same charge, does that mean they have the...

note: m = relativistic mass ##m_o## = rest mass v = velocity of the objectQuestion 1: If a particle is moving at relativistic speeds what would it's kinetic energy be? I think it's ##K.E. = \frac{1}{2} m_o v^2## and my friend thinks it's ##K.E. = \frac{1}{2} \frac{m_o...

If I take a spring with clamps and I weight that system accurately. Then I compress the spring and clamp it thus giving it potential energy. If I now weigh the clamped spring I should see an increase in mass because of the added energy. Is this the case and something that could be proved in the...

A standard 12 gram cartridge contains both liquid and gaseous CO2 at 850psi. Assuming we are venting to atmosphere at sea level, how much energy can be extracted from the cartridge? We know it will expand to 12 grams * 22.4 liters/ 1 mole (44grams) = 6.1 liters. But how much energy did...

In his classic textbook, Callen remarks that I have labelled the claims (1) and (2). I am not sure about either. For the first, I have tried to proceed as follows (all equations are from Callen's second edition and all 0 subscripts are with respect to some reference state of an ideal gas): I...

Suppose you stand on a spherical permanent magnet in space and you hold an iron ball in your hand, you can neglect the gravity force by this magnet mass. You stand and throw the iron ball upwards with some kinetic energy, the ball will eventually stops at some height because it is attracted by...

In Chapter 5 of his famous textbook on thermodynamics, Callen argues for the "equivalence" of the maximum entropy (Max-Ent) principle and the minimum energy (Min-En) principles. I quote from Callen first: As far as I know (though Callen never makes this explicit in what, I think, represents...

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