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 [tag:energy-conservation] if it is specifically about its conservation.

learn more… | top users | synonyms

-2
votes
1answer
83 views

How to heat water to 80°C? [closed]

I'm trying to figure out an easy water to get 80°c to consistently make the perfect cup of coffee. Let's assume room temperature water is 22°c. What is the ratio of boiling water to room temp water ...
-2
votes
1answer
274 views

How momentum/energy is distributed in a elastic collision? [closed]

We know from conservation of momentum or energy that energy (lets think about one quantity at a time) is conserved before and after collision. But how the energy is distributed between the bodies? I ...
-2
votes
1answer
142 views

The time is a type of energy ?

You know energy is necessary for the occurrence of an event . Time is also exactly neccessary for the occurrence of an event. If there is no time , there will be no event. I mean time is a type of ...
-2
votes
1answer
231 views

Why are electrons in one atom attracted to negative electrons in another atom? [closed]

Why or for what purpose is this attraction purposeful or what is the reasoning behind why these energy particles are drawn to each other? Any proven results, or proposed theories of your own, or ...
-2
votes
2answers
355 views

Infinite Energy from Bobbing

Could this device theoretically continue in motion forever? If not, why not? (click below for images): Device description. Device process. The device is less dense than air, so it rises. The ...
-2
votes
3answers
388 views

Is the continuous transformation of energy from one form to another one free? Or it consumes some quantity of who knows what?

Sorry for the unclarity. I probably created some bias in your mind having tagged my question with energy-conservation and conservation-laws. I simply consider that, relatively independently of ...
-2
votes
3answers
943 views

Anti-laser: How sure we are that energy is transported?

Reading this PE question can-we-transport-energy-over-infinite-distances-through-vacuum-using-light, a related question arises naturally: Is energy transported (by light)? -- (I did believed in this ...
-2
votes
2answers
56 views

How fast does an object have to be going to turn into energy [closed]

Albert Einstein's equation, $E=mc^2$, says that an object has to be going at the speed of light squared to turn into energy. How fast would this be in miles per hour?
-2
votes
1answer
105 views

Quantum mechanics: Finite square well problem

What will happen if the potential is less than 0, for instance $V(x)=-10eV$. Is this means there will be no bound states? Since solution to the time independent Schrodinger equation (those discrete ...
-2
votes
2answers
58 views

Difference between two equations

So again I have two equations: $$K= \frac{1}{2} m v^2 + \frac{1}{2} I \omega^2$$ And $$K_w = \frac{1}{2} I \omega^2 $$ What's the difference between these two? Thanks.
-2
votes
1answer
233 views

Can magnetic energy be used to create a magnetic motor which can power vehicles and machines? [closed]

Can magnetic energy be used to create a magnetic motor which can power vehicles and machines?
-2
votes
1answer
313 views

Does the particle vibrate in 3D space? [closed]

As far as I know, particles vibrate with a frequency and wavelength determined by their energy level. Is this vibration in 3D space?
-2
votes
1answer
164 views

Hamiltonian in 2-dimensions? [closed]

I am trying to construct a Hamiltonian for a system in 2 dimensions using Matlab. I am not sure how this Hamiltonian will look like in matrix form. If somebody can help me visualize this matrix that ...
-2
votes
1answer
247 views

Mathematical question on Collisions [closed]

A 2.5kg ball travelling with a speed of 7.5m/s makes an elastic collision with another ball of ...
-2
votes
1answer
109 views

Total Energy Stored in Seven Capacitors [closed]

The capacitive network shown in the figure is assembled with initially uncharged capacitors. A potential difference, Vab = +100V, is applied across the network. The switch S in the network is kept ...
-2
votes
1answer
123 views

Magnitude of work

I am a little bit confused on the concept of work. By definition, work done by a constant force of magnitude F on a point that moves a displacement s in the direction of the force is W = Fs. So lets ...
-2
votes
1answer
103 views

Mathematical Modelling for Efficiency of PV thermal technology

As the efficiency of PV thermal or wind energy decreases with time(from the installment). Is there any mathematical model that gives its relation with time. i.e., whether it is a linear decrease or ...
-3
votes
1answer
59 views

What do I need to know to calculate the price per km for plug-in hybrid or electric cars? [closed]

Knowing the per kWh price of electricity, what other factors are needed to calculate how much would one pay per km traveled on electric power compared to gasoline power? EDIT: For example, the ...
-3
votes
2answers
534 views

Alternative derivation for the capacitor energy equation [closed]

I hope this is the right place for this kind of post. A friend is trying to derive the equation for the energy stored in a capacitor by analysing the change in potential on one plate when the ...
-4
votes
2answers
188 views

Street Light Interference Phenomenon [closed]

Is there a scientific approach that can explain the street light interference phenomenon? Everytime I walk past a Streetlight it turns off.
-4
votes
1answer
89 views

About how much force would something have to exert to be effectively unstoppable? [closed]

Assuming an object is moving in a straight line propelled by a force. How much energy would that force have to exert so that there are no known forces or objects that could stop it from moving in that ...
-4
votes
2answers
2k views

Is the total mass of the universe constant in time? [duplicate]

Is the total mass of the universe constant in time?
-4
votes
2answers
1k 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?
-4
votes
1answer
61 views

Does thermal energy change within a chamber depending on what's in it, where it is, what it is?

I have noticed that some people will say that, when you put more mass in an oven, it takes longer for both to cook than if just were one. Some others will say that timings are the same. Assume we ...