Questions tagged [dissipation]

The tag has no usage guidance.

247 questions
Filter by
Sorted by
Tagged with
66 views

Can thick fur isolate against heat?

I started writing this question on pet.SE but realised after a while that I think it has more to do with physics than pets but if some admin disagrees, please move it back to pets. I have heard ...
40 views

Is there a formula showing the relationship between the number of iron cores and the output voltage of a transformer?

I know the relationship between number of turns, current and voltage of a transformer, but is there a formula showing the relationship between the number of iron cores and the output voltage of a ...
176 views

What's the relationship between the tension of string and the decay rate of its vibrations?

It seems that the more tension on the string, the more slowly the sound would decay after being plucked. Is there a formula relating the two? How is it derived?
51 views

Can a Peltier/Seebeck cell transfer energy from a “thermally insulated” system converting (a part of) thermal energy into electrical energy?

Suppose you have a closed system, as per the schema attached below, which walls are thermally insulated. Suppose you want to reduce the temperature of the fluid inside the closed system, without ...
93 views

How do electrons lose their kinetic energy in ideal wire?

Electrons keep accelerating due to the electric field (produced by the battery) along the circuit. So electrons gain kinetic energy, hence their drift velocity changes. But this is not the case: ...
211 views

Determination of spring constant $k$ for an elastomer

Primary Question: How can you determine the spring constant $k$ of an elastic material? I was recently tasked with finding the spring constant for a series of elastomeric materials, the first of ...
114 views

PT-symmetric hamiltonians: Transition from non-dissipative to dissipative system

It is known that Spectrum of a non-hermitian hamiltonian is complex ($E_n-i\gamma_n$) and they represent the dissipative system. eg, Damped harmonic oscillator(DHO), where $E_n$ are the energies of ...
44 views

Reduce temperature of fluid inside an isolated system without dissipating heat

Suppose you have a perfectly isolated system filled with a fluid, which cannot transfer heat nor matter to the external environment. Suppose you want to reduce the temperature of the fluid within ...
3k views

Why can't we ascribe a (possibly velocity dependent) potential to a dissipative force?

Sorry if this is a silly question but I cant get my head around it.
316 views

Why does a longer string vibrate longer before the damping brings it to rest?

While performing string vibration experiments under the boundary condition that both ends are fixed, I observed that the damping of the wave is much larger when the size of the string is smaller and ...
22 views

68 views

What is the difference between Non-Conservative and Dissipative?

We often hear these terms. However, they are often confused to be synonyms, but they are not. What are the rigorous definitions of them?
51 views

Sign of the work done by dissipation forces

I don't understand this passage from the book I'm reading: Physically, it is clear that a system cannot be conservative if friction or other dissipation forces are present, because \$\mathbf{F}\...
51 views

Perpetual Motion Machine 1: Magnetic Superconductor Loop Generating Energy with Piezoelectrics [closed]

I know there are a lot of perpetual motion machine designs out there, but I haven't found one that looks like this one. I will use this diagram. Assume the entire ring is made of a superconducting "...
59 views

Potential, Kinetic, Thermal Energy?

When things move, potential energy turns into Kinetic energy, right? Then how does Kinetic energy convert to thermal energy?
73 views

What is complex frequency? [closed]

I am learning EE, and about complex frequencies, but what is its physical meaning? What is it used for? Why is it? And only happen in the laplace transform?
108 views

what are the sources of energy loss for a ball rolling down slope?

I am experimenting in lab with an iron sphere rolling down a smooth aluminum ramp. The final velocity is smaller than the one predicted assuming energy conservation (see calculations below), which ...
9k views

Why can't we make a perpetual motion machine by using a magnet to pull up a piece of metal, then letting it fall back down? [duplicate]

Obviously, a perpetuum mobile isn't possible by any law in physics, because energy can't be "created" or "destroyed", only transformed. This said, I've had an idea for a perpetuum mobile and can't ...
40 views

Damped drive oscillating systems

I am currently looking at the theory of find the viscosity of and object through damped harmonic motion, and tho it can be done there is obviously a limitation with regrades to the medium. If the ...
118 views

Why friction causes energy to be lost in terms of heat when it appears to be an energy transfer mechanicsm?

For example, when we move/walk, we apply a force (via friction) on earth, and the earth in turn on us. So essentially I see it as an energy transfer as follows: Suppose I move in same direction as ...
50 views

LC-circuit and the current

A capacitor and a coil are charged in the LC circuit. When the circuit switch is closed, the current starts to flow. In theory the oscillations and the current do not deteriorate, but why in reality ...
37 views

Lagrangian for first order equation of motion? [duplicate]

Let us have the following equation of motion (it might not necessarily correspond to a physical system): $$\dot{x} + a \cdot x + b \cdot x^2 + c=0.$$ I would like to deduce the corresponding ...