Understanding Work and Energy Transfer: The Relationship and Implications

  • Context: Undergrad 
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Discussion Overview

The discussion revolves around the concepts of work and energy transfer, particularly in the context of physical systems and gravitational forces. Participants explore scenarios involving a man pushing objects and the forces acting on the moon in its orbit around the Earth, questioning the implications of work done and energy output in these contexts.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants define work as the transfer of energy through the application of force over a distance, questioning whether energy output occurs when no movement is achieved.
  • One scenario describes a man applying force to move an object, concluding that work is done when movement occurs, but raises the question of energy output when no movement happens.
  • Another scenario discusses the gravitational force between the Earth and the moon, suggesting that while a force exists, it does not result in work being done, leading to confusion about energy sources.
  • Some participants argue that the analogy of a man pushing an object is flawed, emphasizing the distinction between energy input (calories burned) and work output (movement of the object).
  • Others assert that gravity does perform work on orbiting bodies, providing examples of energy changes in satellites during their orbits.
  • There are claims that the work equation may not adequately describe the energy dynamics in gravitational systems, with some participants expressing skepticism about the conservation of energy in these contexts.
  • Discussions also touch on the idea that forces arise from attraction without an initial energy input, raising questions about the nature of energy in gravitational interactions.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the relationship between work, energy output, and gravitational forces. There is no consensus on whether the work equation accurately represents these dynamics, and the discussion remains unresolved.

Contextual Notes

Some participants highlight limitations in understanding the work equation and its application to gravitational forces, suggesting that assumptions about energy input and output may need further exploration.

  • #211
Type of cliff would include it's height from the ground (or core). I've already said that you would have to state the point at which y-position is 0.
 
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  • #212
"UrTalk" was saying that ON the cliff, the ball has no potential energy because it's still touching the ground, OFF the cliff it does have potential energy because it has a distance to reach ground

Tom is saying that you're always measuring potential energy to the bottom of the cliff, even if the ball is sitting on the GROUND at the Edge of said cliff.

just clearing up where people are arguing from (which really isn't part of an argument in the first place, i guess we need to re-focus)
 
  • #213
No, that is not what I was saying. Try again.
 
  • #214
urtalkinstupid said:
Type of cliff would include it's height from the ground (or core).

And as I keep telling you, the height from the ground is all you need to know. You do not need to know anything about the cliff at all. If you took a picture of the bowling ball with a long measuring stick in the background and told me the mass of the ball, and edited out the cliff, I could still tell you what the GPE is with the ground as the datum.

I don't know how to make it any clearer than that that the cliff is purely incidental to the setup.

I've already said that you would have to state the point at which y-position is 0.

You're sending mixed signals then, because the "real definition of PE" by itself does not include the datum.
 
  • #215
urtalkinstupid said:
No, that is not what I was saying. Try again.

That's exactly what you were saying.
 
  • #216
So, is it the type of cliff that is 385m above ground or the type that is 386.3m above the ground?

I simply said that to mess with you people...wow, you people are freaking serious.
 
  • #217
urtalkinstupid said:
I simply said that to mess with you people...wow, you people are freaking serious.
Okay, that's enough for me. Wave bye-bye.

- Warren
 
  • #218
urtalkinstupid said:
I simply said that to mess with you people...wow, you people are freaking serious.

No, you said it because you had a serious misconception about gravitational potential energy, which is why I corrected you. But rather than admit the error and thank me (as I would do in the extremely unlikely event that the shoe is ever on the other foot), you backpeddaled like a know-it-all brat who couldn't possibly make a mistake.
 
  • #219
urtalkinstupid said:
I simply said that to mess with you people...wow, you people are freaking serious.
Interesting catch-22 you put yourself in there: on the one hand you could admit being wrong, learn something and gain our respect, on the other hand you could admit being a troll and a menace to this forum. Interesting choice you made. But it does simplify our job somewhat...
 
  • #220
i knew they were trolls from day one, but nooooo. no one listens to me...
 

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