Mechanical Energy: Where Does It Go?

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Discussion Overview

The discussion revolves around the fate of mechanical energy in a pendulum system, specifically addressing the question of where the mechanical energy goes when the pendulum eventually stops swinging. The scope includes concepts of energy conservation, dissipation, and the effects of non-conservative forces in a real-world context.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions the fate of mechanical energy when a pendulum stops swinging, seeking clarification on energy conservation principles.
  • Another participant suggests that the mechanical energy is dissipated as heat, primarily due to wind resistance and the flexing of the support structure.
  • A request for a detailed explanation is made, indicating a desire for deeper understanding of the energy dissipation process.
  • Concerns are raised about the application of the law of conservation of energy, with a participant noting that gravitational potential energy and kinetic energy should remain constant, except for minor heat losses.
  • A later reply emphasizes that energy is indeed conserved but is lost to the surrounding environment through friction and drag, highlighting the role of non-conservative forces in real-world scenarios.
  • There is a caution against misinterpreting conservation of energy principles, stressing that the pendulum's motion is affected by its interaction with the environment.

Areas of Agreement / Disagreement

Participants express differing views on the extent and mechanisms of energy dissipation, with some agreeing on the role of heat and drag, while others question the completeness of these explanations. The discussion remains unresolved regarding the full understanding of energy loss in this context.

Contextual Notes

Participants note the influence of non-conservative forces and the complexities of real-world interactions, which may not align with idealized physics scenarios. There are unresolved aspects regarding the specific contributions of various forms of energy dissipation.

isyang94
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When a pendulum is let go from an elevated area, it will eventually stop swinging. But if this occurs then where had the mechanical energy gone to?
 
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It's dissipated as heat, mostly from wind resistance, some from the flexing of whatever's holding it up.
 
explain in details please
 
because according to the law of conservation of energy, the gravitational potential energy and the kinetic energy would just stay the same the whole time but it is only slightly dissipated by heat, where else does it all go?
 
You were already given the correct answer.

It's not swinging in a vacuum. The energy is dissipated through friction with the air (drag) while it is in motion and through heat as whatever holds it up is flexed. Like you said, energy must be conserved and HAS to go somewhere. Since the pendulum only interacts with the surrounding environment, then that is where it has gone.

Don't put your own interpretation onto conservation of energy because you're taking an introductory physics class. Friction is a NON-CONSERVATIVE force, meaning that you cannot consider the motion of a pendulum in the real world to be path independent. The path that it travels causes drag, and a reduction of the energy within the pendulum.
 

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