Source of Energy in a Field of Forces

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Discussion Overview

The discussion revolves around the source of energy in fields of forces, particularly in the context of gravitational fields. Participants explore the concept of energy conservation in isolated systems and how energy is transferred or transformed within these fields.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the source of energy provided by fields of forces, specifically asking about gravitational fields and their role in energy transfer.
  • Another participant suggests that the field itself is the source of energy, indicating that the field possesses an energy density that decreases as energy is transferred.
  • A different participant explains that an object in a gravitational field has potential energy, which converts to kinetic energy when the object falls, emphasizing the conservation of energy in this process.
  • Another contribution reiterates the conservation of energy, noting that when a rock is dropped, it gains kinetic energy, which can be returned as potential energy when lifted back up, without continuous energy expenditure.
  • A request for further clarification on the concept of energy density in fields indicates a desire for deeper understanding of the topic.

Areas of Agreement / Disagreement

Participants express differing views on the source of energy in fields, with some asserting that the field itself provides energy while others focus on the transformation of potential energy to kinetic energy. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants have not fully defined the terms related to energy density or the mechanisms by which energy is transferred in fields, leaving some assumptions unaddressed.

Lukeblackhill
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good evening!

My question is the following: it is well stated that energy is conserved in any isolated system, and we can in most circumstances expand our system to a many-steps conversion of energy, but always conserved. The classic example could be the energy of the sun stored in form of chemical energy in the plants, which are eaten by a man that converts such an energy into motion when he pushes a ball, and so on.

But when we consider fields of forces, who is the source of the energy they give to things (like an object who gains energy from the gravitational field as it gets near to the earth)?

Thanks!
Cheers!
 
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Lukeblackhill said:
But when we consider fields of forces, who is the source of the energy they give to things (like an object who gains energy from the gravitational field as it gets near to the earth)?
The field itself. The field has an energy density which is reduced.
 
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Lukeblackhill said:
good evening!

My question is the following: it is well stated that energy is conserved in any isolated system, and we can in most circumstances expand our system to a many-steps conversion of energy, but always conserved. The classic example could be the energy of the sun stored in form of chemical energy in the plants, which are eaten by a man that converts such an energy into motion when he pushes a ball, and so on.

But when we consider fields of forces, who is the source of the energy they give to things (like an object who gains energy from the gravitational field as it gets near to the earth)?

Thanks!
Cheers!
An object in Earth's gravitational field has potential energy. When that object falls from a height to the ground, (some of) that potential energy is converted to kinetic energy.
 
Note also that energy is conserved. Drop a rock and it gains kinetic energy vs earth. pick it back up and you give it back as potential energy. And there is no continuous expenditure of energy involved.
 
Dale said:
The field itself. The field has an energy density which is reduced.

Could you explain that in more detail, please? I haven’t found a good material on the matter.
 

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