Energy Confusion (Conservation of Energy?)

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Discussion Overview

The discussion revolves around the statement regarding gravitational potential energy and its implications for movement on higher ground, particularly in relation to non-conservative forces such as friction and air resistance. Participants explore the validity of the statement and its underlying assumptions, focusing on theoretical and conceptual aspects.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants agree that getting to higher ground increases gravitational potential energy.
  • Others question the assertion that this increase would decrease the effects of non-conservative forces, suggesting it seems illogical.
  • One participant argues that friction is necessary for movement, implying that a lack of friction would hinder rather than help movement.
  • Another participant points out that air resistance decreases with height due to lower air density, but also notes the practical consideration of reduced oxygen availability at higher altitudes.
  • A technical explanation of friction is provided, indicating that the normal force, which is influenced by gravitational force, affects friction, but the variation in gravitational force with height is minimal.

Areas of Agreement / Disagreement

Participants generally do not reach consensus, as there are multiple competing views regarding the implications of increased gravitational potential energy and the role of friction and air resistance in movement.

Contextual Notes

There are unresolved assumptions regarding the definitions of "moving easier" and the specific non-conservative forces being referenced. The discussion also highlights the small variation in gravitational force with height, which may affect the friction experienced.

Generally Confused
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Anyone know if the following statement is true (and why)?

"Getting to higher ground would increase his gravitational potential energy, decreasing the effects of non-conservative forces, which would allow him to move easier."

CLARIFICATION: "move easier" refers to a lack of friction and not the slight increase in gravitational force. Do with that what you will.
 
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Hmmm. I can't think what would "allow him to move easier" as g on higher ground is almost undetectably different from g at sea level.
Where did you find that statement?
 
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Generally Confused said:
Getting to higher ground would increase his gravitational potential energy
This part is true

Generally Confused said:
decreasing the effects of non-conservative forces, which would allow him to move easier
This part seems weird, like it was written by a drunk physicist.
 
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Friction actually makes it easier to move. If there was no friction driving and walking would be impossible.
 
Generally Confused said:
Anyone know if the following statement is true (and why)?

"Getting to higher ground would increase his gravitational potential energy, decreasing the effects of non-conservative forces, which would allow him to move easier."

CLARIFICATION: "move easier" refers to a lack of friction and not the slight increase in gravitational force. Do with that what you will.
Do you mean friction or air-resistance? The air resistance is dependent on the density of air, which does decrease with increasing height. However, in practice a person would have to account for the fact that there would be less oxygen present due to the lower pressure.

The frictional force is, to a first approximation, usually given by f=μN, where μ is the coefficient of friction and N is the normal force.
Since N in many cases is opposing the gravitational force acting on the object, a change in g could result in a change of friction with height, but as @sophiecentaur noted, the rate at which g varies with height is small (the difference between g at sea level and a height corresponding to the top of Mount Everest can be calculated to be about 0.03 ms-2, even at the ISS, g is about 0.9 times that at sea-level), so in practice there would be little variation in friction.
 
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