Questions tagged [potential-energy]
Potential energy is the energy of a body or a system due to the position of the body or the arrangement of the particles of the system.
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Electric potential energy in circuits [on hold]
Is it possible to have a circuit in which the potential difference across a battery in the circuit is zero? If so give example, if not explain why
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1answer
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Conducting sphere
A conducting sphere is to be charged by bringing in positive charge a little at a time until the total charge is $Q$. The total work required for this process is alleged to be proportional to $Q$ ...
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1answer
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Two point charges
Is it possible to have an arrangement of two point charges separated by a finite distance such that the electrical potential energy of the arrangement is the same as if the two charges were infinitely ...
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1answer
34 views
Potential energy of the oscillator
Is there a difference between the potential energy of an oscillator and the potential energy of the spring which is associated with? When we compress a spring horizontally without any object ...
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1answer
25 views
Potential energy-Conservative forces
Does potential energy exist because conservative forces exist?
Can a system of objects that interact with dissipative forces have potential energy?
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4answers
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Potential energy of system or particle of the system?
Why in gravitational potential or also electrical potential energy we refer to potential energy of 1 particle of the system and not whole system? for example in system earth and a ball we speak about ...
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2answers
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Potential energy is zero at infinite distance
We set the electrical potential energy to be zero in infinite distance to calculate potential energy at a distance $r$. But how is it possible from infinite distance to end up with finite distance? ...
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2answers
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Elastic potential energy and springs
The formula for elastic potential energy(for a spring) has been derived by assuming the following things:
1.Work done by a deforming force on a spring from a relaxed state (state where spring is not ...
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4answers
82 views
Why $g$ is not negative in potential energy $= mgh$ formula
For eg. A boy of mass 55 kg runs up a staircase of 50 steps in 10s. If the height of each step is 10 cm, find his power.
My question is here why are we not taking g as negative as boy is moving up ...
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1answer
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When are thermodynamical potentials conserved?
I have studied that are 4 thermodynamical potentials wich are useful, which are the internal energy $U$, the helmholtz function $F$, the Gibbs free energy $G$ and the enthalpy $H$:
$$dU=TdS-PdV$$
$$...
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1answer
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2 body problem question
I am taking a classical mechanics course and i am struggling to determine the equilinrium points for this potential $$Q= -(k/r) + ar + (L^2/mr^2).$$ The problem is that i have to solve a cubic ...
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1answer
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Goldstein's proof that $W = -\Delta V$: Why is $\nabla_i V_{ij} = \nabla_{ij} V_{ij}$?
On page 11 of the third edition of Goldstein's Classical Mechanics, the book claims that
If the difference vector $\textbf{r}_i - \textbf{r}_j$ is denoted by $\textbf{r}_{ij}$, and $\nabla_{ij}$ ...
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1answer
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Total Gravitational Potential between two objects? [closed]
It's taken me a while to formulate what i've been thinking about, but what is the total gravitational energy between two objects, not the instantaneous force between them?
For example: imagine two ...
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2answers
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Can the mass of a hydrogen atom be calculated in a gauge-invariant way?
Please excuse the lengthy question. It involves an interesting controversy which has arisen in discussions on this site:
Energy/mass of Quantum Vacuum
Relative potential energy vs Absolute potential ...
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0answers
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What are the “basic things” we need in physics to define any kind of energy, including “mass”?
After having commented an answer there:
Relative potential energy vs Absolute potential energy,
I realised that the energy concept may be much more subtle than what we usually believe, even if we ...
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3answers
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Relative potential energy vs Absolute potential energy
I have seen in many textbooks and sources which say that we can't experimentally measure potential energy but we can measure differences in potential energy.
$$\Delta U_g=-W_g$$
Choosing zero ...
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1answer
31 views
Conversion of potential energy in other forms of energy
Can potential energy be directly converted into other forms of energy rather than first converting to kinetic energy then to other forms of energy
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2answers
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Series expansion of $N$-particle potential energy
I am trying to understand the so-called Taylor expansion (or series expansion) of potential energy of a system of $N$-particles. This expanded form is stated without derivation in some molecular ...
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1answer
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Feynman Lecture Principle of Least Action: Glossed over Taylor expansion?
His initial one dimensional derivation of Newton's Second Law using the Principle of Least Action, I believe is fairly concise and easy to read. However, I did get hung up on his use of the Taylor ...
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2answers
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Path independence in a gravitational field
In all of the below remarks, I am considering an object (a "mass") moving around above the surface of the earth.
What are some physical examples of situations that demonstrate path independence in a ...
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2answers
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Proof of total energy is constant in a central force field
I saw many proofs of total energy is constant in a central force field. But all the proofs end up showing this formula $$m[{\dot r}^2 + r ^2{\dot \theta}^2 ]+ \int f(r)dr = E$$ is constant. But ...
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1answer
26 views
What definition of change in potential energy applies to a multi-particle system?
I read a text:
We define change in potential energy of the system corresponding to conservative internal forces as:-.
$$\Delta U = -W = -\int \mathbf{F}\cdot d\mathbf{r}$$
as the system goes ...
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2answers
140 views
Isn't definition of potential energy a vague definition? [duplicate]
Why do we define potential energy? If we know the essence of defining work then isn't defining potential energy useless?
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1answer
64 views
Conservation of mechanical energy proof
Using Newtonian mechanics, how does one prove that the change in mechanical energy of a classical system of particles is equal to the work done by non-conservative forces? What assumptions are made? ...
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2answers
70 views
Why do we include $x$ in this Spring Equation?
I am currently in Physics 1 and we are learning about Energy. This may sound like a dumb question but I am currently trying to understand this. Here is the question of the problem:
A 10kg block is ...
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2answers
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Where do the Lennard-Jones dimensionless/reduced units come from?
I'm a little bit confused as to where the expressions for the Lennard-Jones Potential Dimensionless units shown in this Wikipedia chart come from. I know they're derived from the L-J force equation ...
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0answers
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The Electric Potential Energy of a Line of Charge
I want to find the electrical potential energy of a finite line of charge with length "L". I understand how to find the potential but not the potential energy. I´m imagining we would start with an ...
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1answer
44 views
System of two masses interacting and the notion of work [closed]
Assume an isolated system consisting only of the earth and a basketball interacting through the gravitational force: No air, no other planets/stars etc. Are the following statements accurate?
The ...
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2answers
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Accurate Equation for Earth's Gravitational Binding Energy
This is a relatively important question for anyone who can answer it. I am trying to find the equation that accurately solves for Earth's Gravitational Binding Energy. The information below is from ...
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1answer
43 views
Internal work in system made up of a ball and the earth
Assume I am considering my system to be the earth, a ball, and the gravitational interaction between them. No air resistance. Assume the ball has a nonzero initial velocity upward. I understand there ...
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2answers
159 views
What is the potential of mean force?
I've come across the term potential of mean force (PMF) in polymer physics, colloidal physics etc., but have not come across a complete definition.
As far as I understand, the PMF determines the ...
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1answer
33 views
How are batteries affected on planes? [closed]
I'm currently an engineer and was fascinated at how technology came to be and how we were able to find out that we can take energy and essentially store it for a later time. I was thinking about ...
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3answers
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Converting potential energy to kinetic energy
I know how potential and kinetic energy interrelate when you drop anything.
But is it a general understanding in the community that a change in potential energy is always kinetic energy? I am ...
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0answers
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In any potential force field, there exists at least one periodic motion of the body?
Talking about
a rigid body fastened to a stationary point and located in an arbitrary potential field
V.I. Arnol'd concludes that
In any potential force field, there exists at least one ...
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1answer
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Conservation of energy on a spring. When are forces positive and negative?
I'm doing physics problems on my own and I cannot figure out when Potential Energies (U) are supposed to be positive and when negative in a Conservation of Energies problem.
Take for example this ...
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Escape velocity for positive potential energy
In a case where we are just given a potential energy function (always positive), how do you know what would the escape velocity be? What does escape velocity mean?
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0answers
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Potential energy of and forces within a massive spring
So, I've been doing problems related to calculating the time period of SHM for a spring mass system where the mass is M, and the spring has a finite mass m.
The standard method of dealing with this ...
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3answers
82 views
Does potential energy belong to an object or the system?
The gravitational potential energy of an object is given by mgh where h is the distance from the chosen zero potential reference level.
Usually we talk as if the potential energy belong to the object ...
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4answers
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Formula for potential energy? Conservation of energy?
How would we know what formula to use for potential energy?
In my class, $mgh$ was used, but when dealing with a spring, it's ${1\over2}kx^2$. Is that because that's the elastic potential energy ...
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1answer
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Gravitational potential energy with both bodies moving [closed]
When deducing the formula for the gravitational potential energy of one body in relation to the gravitational force of another body, my teacher assumed that one body was standing still. I tried ...
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1answer
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Finding G.P.E. of a system of particles
we want to calculate the P.E(potential energy) of a system containing 3particles p1,p2,p3.the point of observation is P.so now we should add up the P.E at P due to p1,p2,p3 to get the net potential ...
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3answers
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Can we theoretically guide cold air from high altitude down to the needy cities as free AC?
If you had an insulated tube (approximate size say 15k feet (5km) tall, 50ft (15m) diameter) with the top end open and bottom end closed, would the air in the tube eventually become as cold as the ...
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1answer
290 views
Is it wrong to imagine the gravitational potential of a system based on the center of mass?
I was practising some questions until I stumbled upon a question.
A chain of length $l$ and mass $m$ lies on the surface of a smooth sphere of radius $R>l$ with one end tied to the top of the ...
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1answer
46 views
In vertical circular motion of a mass attached to a rope, where does the elastic potential energy stored in the tension goes?
When a bob is attached to a rope where the rope has negligible mass, the bob undergoing circular motion will have its KE1+PE1 at any point of the circular motion equal to KE2+PE2 at another point of ...
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0answers
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Distance Dependence of Van Der Waals Forces and his Equation of State
I've been trying to reconcile the form of the van der Waals equation of state and the equations from which they are derived. Stop me where I go wrong:
The VDW EOS includes two terms: one for the ...
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1answer
100 views
Doesn't the “Mexican hat” potential give a misleading impression that the barrier height between two vacua is finite?
For $\mathbb{Z}_2$ symmetry breaking in a Classical Field Theory described by a potential $$V(\phi)=\lambda(\phi^2-v^2)^2,\tag{1}$$ there is a finite energy barrier of height $\epsilon=\lambda v^4$ ...
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2answers
211 views
Energy of room. Ideal gas law
I have been following Blundel's "Concepts of thermal Physics" and I got to the derivation of the ideal gas law. And it all made sense, we made a couple of assumptions and approximations, but then I ...
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1answer
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Release of energy during electron jumps [duplicate]
We took up the topic of particle nature of light recently.As the light is quantised when an electron jumps from higher to lower orbit it releases energy but as the energy is quantised it will release ...
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2answers
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Why is the entirity of string tension $T$ included in the potential energy of a string wave?
When calculating the elastic potential energy of a string segment inside a transversal string-wave, it is usually reasoned that the string tension $T$ causes the string segment to stretch as it ...
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2answers
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Thermal energy transfer + combined energy question
In thermal energy transfer, why does the total combined energy of all particles remain constant?
