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.

learn more… | top users | synonyms

0
votes
1answer
100 views

why does water do that?

I found recently that water fills a bottle quicker through only observation if I hold the tube away from the filling water than if I leave the tube inside the bottle. why does that happen? does ...
0
votes
0answers
93 views

Interpretation of contribution of gravitational potential energy to the gravitational field

In terms of General relativity we have as a matter of principle that anything that has inertial mass contributes to gravity. All forms of potential energy have inertial mass, it follows that the ...
2
votes
3answers
194 views

Is there energy stored when iron is magnetized?

When a piece of iron is magnetized, and the domains are aligned, Is there energy stored? If so, how much energy is stored? If there is an attraction between that same iron and the source of the ...
2
votes
2answers
336 views

Signs in proof of gravitation potential energy (GPE)

Proof of gravitational potential energy. Work done by gravity in bringing mass from infinity to a distance of $r$ between masses. When we use the integration formula and arrive at the answer we ...
2
votes
0answers
589 views

Differences between time-independent and time-dependent Schrödinger equation for potential generation

Suppose I wanted to develop a potential describing the interaction between two lithium atoms. One way to do this is to calculate the energy between the two lithium atoms for various distances and ...
1
vote
1answer
2k views

Difference between voltage and potential energy in a capacitor

I'm confused about the difference between voltage and potential energy in a capacitor. Suppose you have a capacitor with a voltage V and capacitance C, and you release a particle with charge $+Q$ from ...
1
vote
2answers
229 views

Can a particle with non-zero angular momentum pass through the center of a spherical potential?

Suppose you have a particle of mass $m$ moving in a potential $V(r) = -\frac{k}{r^2}$, with $r^2 = x^2+y^2+z^2$ and $k > 0$. Since the angular momentum $l$ is conserved, the particle will move in a ...
2
votes
1answer
200 views

Gravitational binding energy and integrated potential energy not the same?

Before looking up the formula for the gravitational binding energy of a uniform sphere, I simply figured that the general formula for binding energy of an arbitrarily-shaped mass distribution would be ...
1
vote
1answer
389 views

potential energy change in conservative field

Is it true that potential energy of a particle always decreases in the direction of conservative force acting on it?
1
vote
2answers
71 views

Capacitor's voltage

Imagine I have two plates that form a capacitor, so the magnitude of the charge in each plate is, let's say, $Q$. So, the force, in respect to the distance $d$, is gonna be: $$F(d) = ...
3
votes
1answer
131 views

Why do organisms accumulate potential energy?

I can understand that animals need some battaries to run. But, we learn that plants serve like batteries for animals because they accumulate the sun energy in the first place! You can eat them or burn ...
1
vote
2answers
324 views

Deriving the Lorentz force from velocity dependent potential

We can achieve a simplified version of the Lorentz force by $$F=q\bigg[-\nabla(\phi-\mathbf{A}\cdot\mathbf{v})-\frac{d\mathbf{A}}{dt}\bigg],$$ where $\mathbf{A}$ is the magnetic vector potential and ...
0
votes
1answer
71 views

We create systems with different values of Energy? [closed]

I understand that Energy is a conserved quantity in a system. A number, that's always the same to the system. However, don't we determine such a number? I mean, we can create systems(Or study them ...
2
votes
2answers
2k views

Why potential energy of a dipole in an electric field has a negative sign?

In the following equation $$V = -\mathbf{P}\cdot \mathbf{E}$$ why I have to take Potential Energy as negative. Is there any simple reason behind this ? I am preparing for my high school ...
0
votes
0answers
38 views

The conservation of energy when a spring is placed in acid [duplicate]

Stretch a spring out and give it a bunch of potential energy. Lower the spring into a vat of acid, disolving the spring into nothingness. Where did the potential energy go?
1
vote
2answers
321 views

Elastic potential energy of compressed spring? [duplicate]

If a compressed spring is dissolved in acid what happens to the elastic potential energy of the spring?
1
vote
0answers
77 views

Deriving the curve of a cantilever

Essentially, there is a beam of length L and negligible mass sticking out of a wall with a mass Mg hanging at the end of it. We are given an equation for elastic energy (which I don't think needs to ...
1
vote
3answers
5k views

Why is Energy = Voltage x Charge, and how to prove that?

As you know the equation $\mathbf{E=V\times Q}$. Where: $\mathbf E$ is the energy measured in joules, $\mathbf V$ is potential difference (Voltage), $\mathbf Q$ is the charge. So my qustion is: ...
2
votes
1answer
536 views

Dominos vs. Conservation of Energy

In this video a single flick of a finger tips 116000 dominos. Domino video I understand the work that needs to be done to move 116000 pieces (at least 100 kilos) of plastic is greater then that ...
0
votes
0answers
102 views

Potential energy: Electric field two spherical charges

I want to determine the potential energy of two equally charged spherical charges by using the equation: $V_{pot}= \int_V \frac{1}{2} \epsilon_0 E^2 dV$ and therefore I was wondering what I has to ...
0
votes
1answer
2k views

Potential energy of the dipole-dipole interaction for two parallel dipole moments

I am looking for an equation that gives me the potential energy of the interaction between two parallel dipoles.
0
votes
1answer
292 views

overall energy transformation as a diver moves downwards through water [closed]

What is the answer to the following MCQ? A swimmer dives into a very deep pool at high speed. He slows down as he moves towards the bottom of the pool. What is the overall energy ...
3
votes
2answers
253 views

Coincidence, purposeful definition, or something else in formulas for energy

In the small amount of physics that I have learned thus far, there seems to be a (possibly superficial pattern) that I have been wondering about. The formula for the kinetic energy of a moving ...
-6
votes
2answers
749 views

Is electron volt an alternate unit for electric potential? [closed]

My question is: Can an electron volt be considered an alternate unit for electric potential?
3
votes
2answers
270 views

The “stationary potential energy” condition for static equilibrium in mechanical systems

I've often read that, for a mechanical system which can be described by $n$ generalized coordinates $q_1,...,q_n$, a point $\mathbf{Q}=(Q_1,...,Q_n)$ is a point of equilibrium if and only if the ...
1
vote
2answers
235 views

Potential and Kinetic Energy

In engineering school you learn the basic swing problem. Essentially that there is a transfer of kinetic energy (as seen in the velocity at the bottom of as swing) to potential energy at the top of ...
0
votes
2answers
232 views

What's an “Action” and what does the Lagrangian equation mean exactly?

How and why would a particle take the shortest path? $L=KE-PE$? What's the $KE-PE$ mean in English? I understand the 'mechanics' but not the idea itself. Please explain simply, I do know Calculus ...
0
votes
2answers
5k views

Relation between work, kinetic energy and potential energy

We derived two equations in class. The work done between two points $A$, $B$ is equal to the difference between the kinetic energy at the last point and the one at the first point. The work done ...
6
votes
2answers
180 views

What can be known about the formulas for energy only from the fact that it is conserved?

The question is to figure out how the energy can be derived knowing just one thing: There is a quantity called Energy that is conserved over time. The goal is to get an equation that somehow ...
0
votes
1answer
316 views

Calculate magnitude of force acting on some area by falling object

I have simple question: is it possible to calculate magnitude of force acting on some area by falling object? Let's say I have an object with mass $5\text{ kg}$. I drop that object in height 1 ...
13
votes
2answers
2k views

How does a sponge “suck” up water against gravity?

If I take a sponge and place it in a shallow dish of water (i.e. water level is lower than height of sponge), it absorbs water until the sponge is wet, including a portion of the sponge above the ...
1
vote
1answer
191 views

Do these equations apply to an object on a zip line or slope?

I was looking at the conversion equations for Potential Energy to Kinetic Energy to Velocity here: http://www.ftexploring.com/energy/PE-to-KE.html Would these apply to an object on a zip-line? ...
1
vote
2answers
613 views

Energy stored in a clothespin spring (non linear spring)

I was wondering how one would go about figuring out the energy stored in a spring in a clothespin. When opened the spring is deformed, but I don't have any intuition for why it gets stronger with ...
7
votes
1answer
678 views

Does potential energy in gravitationall field increase mass?

I was just taught (comments) that any type of energy contributes to mass of the object. This must indeed include potential energy in gravitational field. But here, things cease to make sense, have a ...
1
vote
1answer
207 views

Center of mass of a body on an incline

I am trying to reproduce a calculation by Carre et al. (1995) in which they calculate the shape of a droplet on an incline. My issue is in the derivation of the potential energy (essentially the ...
0
votes
0answers
162 views

Derivative of $\epsilon$ in Lennard-Jones equation

I just want to calculate the derivative of epsilon for the following Lennard-Jones equation: LJ = $4\sqrt{\epsilon_{ii} \epsilon_{jj}}$ $[(\sigma/ r)^{12}-(\sigma/r)^{6}]$ with respect to ...
1
vote
2answers
421 views

Kinetic energy of two charged balls at infinite distance between them

If I have two balls with masses and charges $m_1, q_1^{+}$, $m_2, q_2^{+}$, initially held at distance $d$, and then released, how can I know the kinetic energies of each of the balls at infinite ...
5
votes
1answer
380 views

Physics of every-day life: rotating bag of tea

Whilst studying for my physics courses, I like to drink tea. Today, I noticed that if you pull a bag of tea out of a hot cup of water, it gradually starts to rotate, picking up speed as time ...
1
vote
2answers
347 views

Potential on a Charged Sheet

I know the field difference across a charged sheet-but what's the potential on a charged sheet? Is it just asymptotic? If we had a thin cylindrical sheet would it be the same? Zero field inside the ...
3
votes
4answers
763 views

Potential energy sign conventions

Almost every book on physics that I read have some weird and non-clear explanations regarding the potential energy. Ok, I do understand that if we integrate a force over some path, we'll get a ...
7
votes
2answers
545 views

Mechanical Equivalent of Heat

Recently I have been looking up James Joule's experiment regarding the mechanical equivalent of heat. After viewing some drawings of the apparatus, I assumed that the lines holding the weights would ...
2
votes
2answers
2k views

Why is potential energy negative when orbiting in a gravitational field?

I had to do a problem, and part of it was to find the mechanical energy of satellite orbiting around mars, and I had all of the information I needed. I thought the total mechanical energy would be the ...
1
vote
2answers
372 views

Center of mass problem

According to the definition of potential energy, we use $U= mhg . $ In the figure below , A thin uniform rod of mass m and length h is positioned vertically above an anchored frictionless pivot ...
1
vote
2answers
289 views

Negative potential energy of gravity

Does the negative potential energy in the gravitational field have to be considered in calculating the total mass of the system in question (because of $E=mc^2$)? If so it seems to me that the ...
2
votes
1answer
266 views

Center of mass error - calculating systematic error in change in PE

Suppose we have to calculate systematic error in change in PE. Let's suppose systematic error due to scale is 1%. I'm confused about the center of mass error. \begin{align} \Delta PE = m*g*h_1 - ...
0
votes
2answers
167 views

Escape velocity to intersection of two gravitational fields

Find the minimal velocity needed for a meteorite of mass $m$ to get to earth from the moon. Hint: the distance between the center of earth and the center of moon is $\approx 60 R_E$, and the ...
11
votes
1answer
1k views

In the Lennard-Jones potential, why does the attractive part (dispersion) have an $r^{-6}$ dependence?

The Lennard-Jones potential has the form: $$U(r) = 4\epsilon\left[ \left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^{6} \right]$$ The (attractive) $r^{-6}$ term describes the ...
1
vote
1answer
993 views

Gravitational potential energy of mass between two planets

Suppose I want to launch a rocket from earth to some point $O$ between the center of earth and the center of moon (on a straight line connecting their centers), where the gravitational force of the ...
1
vote
6answers
1k views

Electrostatic Potential Energy Derivation

How is the boxed step , physically as well as mathematically justified and correct ? Source:Wiki http://en.wikipedia.org/wiki/Electric_potential_energy As work done = $- \Delta U $. for Conservative ...
1
vote
1answer
966 views

Given a potential energy function, find expression of the force of a particle?

This comes from an AP review packet. I'm given a potential energy functon, $$U(r)=br^{-3/2} + c,$$ where $b$ and $c$ are constants, and need to find the expression for the force on the particle. ...