Questions tagged [energy]
Energy is the conserved quantity associated to time-translation invariance and represents the work a system is capable of doing. Use this tag for questions about energy, and consider adding the [energy-conservation] tag if it is specifically about its conservation.
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Why is the potential energy of an element in a string not a negative value?
I am learning about energy in wave motion, specifically about the energy of waves travelling in a string. My textbook gave the equation $$ dU = T(dl - dx) $$
It states that this is the work done by ...
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A spherical void (vacuum) is instantaneously created in an atmosphere of ideal gas: can we approximate the energy involved in the resultant collapse? [duplicate]
Premise
Imagine we could magically / instantaneously create a sphere-shaped void - a near-perfect vacuum - in the atmosphere (or any other similar space filled with a near-ideal gas).
Question
Can we ...
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Is zero-point energy a mathematical artifact?
From Wikipedia, Pauli has said in his Nobel lecture that "It is clear that this zero-point energy has no physical reality". This feels natural - I've always been slightly puzzled by the ...
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Energy in molecular physics
Background (in case it clarifies my question): I'm a 10th-grade school student. We've just learnt about the ideal gas model, the ideal gas law, and the formulae relating pressure, average kinetic ...
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Would a hydroelectric dam produce 100x power on a planet with 100 times Earth’s gravity? [closed]
Imagine an alien civilization has built a hydroelectric dam on a planet where gravity is 100 times that of Earth. The dam is roughly the size and design of the Hoover Dam, capable of producing about 1 ...
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To Find the power of a motion do we need to consider force into velocity or energy per time? [closed]
A trolley is moving at a constant velocity v and sand is being dropped in at m kg/s.So what is the power need to be supplied to keep the trolley moving at same velocity.I suggest two methods
Force x ...
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Relationship of space-time to energy and momentum [closed]
After reading Noether's theoram and many other examples like objects tendency to follow its geodesics in spacetime makes conserved quantities like momentum etc meaningful so , are energy and momentum ...
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Practicality of zero-point for potential energy of a magnetic dipole in a magnetic field
Is there any practical significance of the convention of potential energy of a magnetic dipole in an uniform magnetic field?
Suppose, in a vacuum, a magnetic field runs in the $y$ direction. Now we ...
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Questions about the behavior of a void (vacuum) in atmosphere [closed]
Introduction
I've been doing some research on this topic and I want to:
Confirm my findings
Answer some lingering questions
Premise
Imagine we could magically / instantly create a void in the ...
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Callen's Thermodynamics - how can equilibrium states be specified by internal energy?
I am currently reflecting a bit on the formal structure of the theory presented in Callen's classic text Thermodynamics and an Introduction to Thermostatistics. I was originally going to post a more ...
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Do blueshifted and redshifted light sources have differing energies?
The thought experiment:
Two spaceships are passing each other some distance from a star. Both ships are at relativistic speed, one toward and one away from the star. Should the total energy observed ...
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Is it possible to generate electricity from muons instead of photons?
I understand that solar panels generate electricity by converting photons from sunlight. This made me wonder whether it would be possible to use other types of cosmic radiation, such as muons, to ...
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Zero Energy and Zero Mass
It is a general principle in modern physics that there is no true zero point for energy. A system's energy states can be listed from higher to lower, and one can be assigned "0" by arbitrary ...
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Is $\Delta H$ equal to $\Delta Q_{irreversible}$?
In the proof of spontaneity criterion in constant pressure and temperature, the steps are:
$$\Delta S_{system} - \frac{\Delta Q_{rev}}{T}=0 $$
and
$$\Delta Q_{rev} > \Delta Q_{irrev}$$
So, we may ...
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Confused about the Kinetic Energies of a many-body system
My Question stems from the following problem:
Consider two resting Point Masses, each with mass $m$, which are connected (the connection having no mass). A Force $F$, which is always perpendicular to ...
