Is mechanical energy conservative?

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Homework Help Overview

The discussion revolves around the concept of mechanical energy and its conservation in various scenarios, particularly focusing on the influence of forces such as friction.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the definition of mechanical energy conservation, with some questioning the relationship between kinetic energy changes and energy conservation. Others discuss specific examples, such as a block sliding on a frictionless incline versus one on a flat table with friction.

Discussion Status

The conversation is ongoing, with participants offering different perspectives on when mechanical energy is conserved. There is a mix of interpretations regarding the implications of kinetic energy remaining constant and the role of non-conservative forces like friction.

Contextual Notes

Some participants express uncertainty about the definitions and classifications of forces and energy types, indicating a need for clarification on these concepts.

UrbanXrisis
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is mechanical energy conservative?
 
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No, the mechanical energy of a system might, occasionally be conserved; "conservative"/non-conservative is a way to classify FORCES.
 
I assume you mean: Is mechanical energy conserved? Answer: Sometimes! :smile:

For example: A block sliding down a frictionless incline--mechanical energy (PE + KE) is conserved; but introduce friction, then mechanical energy is not conserved.

Did you have a particular situation in mind?
 
sliding a block on a flat table. I saw that there wasn't a change in Kinetic Energy. So, that means energy is not conserved. I know that the friction force is non-conservative but I wasn't sure about the mechanical energy.
 
UrbanXrisis said:
sliding a block on a flat table. I saw that there wasn't a change in Kinetic Energy. So, that means energy is not conserved.
Why would seeing the KE not change lead you to think that energy was not conserved? :confused:

I know that the friction force is non-conservative but I wasn't sure about the mechanical energy.
Mechanical energy is not a force.
 

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