Objects Moving Apart Under Gravity?

  • Context: Undergrad 
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    Gravity
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Discussion Overview

The discussion revolves around the motion of two balls shot vertically upward from the Earth's surface with different initial velocities. Participants explore the dynamics of their separation under the influence of gravity, questioning whether the distance between the balls accelerates as they ascend and descend. The conversation touches on concepts from classical mechanics and hints at cosmological implications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that the distance between the balls increases constantly, but does not accelerate, as they move further from the Earth.
  • Others argue that while the distance increases, it does not imply acceleration away from each other throughout the entire trajectory.
  • A participant proposes that the relative velocity between the two balls remains constant, leading to a linear relationship in their height difference over time.
  • One participant raises a question about how the scenario relates to cosmology, particularly regarding the universe's expansion and potential contraction.
  • Another participant emphasizes that gravitational acceleration is not uniform due to varying distances from the Earth, suggesting that the lower velocity ball experiences greater acceleration as it descends.
  • There is a request for plotted trajectories to visualize the motion of the balls and confirm or challenge the theoretical claims made.

Areas of Agreement / Disagreement

Participants express differing views on whether the distance between the balls accelerates or increases at a constant rate. Some maintain that the distance increases steadily without acceleration, while others suggest that the dynamics of gravitational acceleration complicate this understanding. The discussion remains unresolved regarding the implications of these motions in a cosmological context.

Contextual Notes

Participants note that the equations used assume a constant gravitational acceleration, which may not hold true at varying altitudes. The complexity of gravitational effects in cosmology is acknowledged, indicating that a more nuanced approach may be necessary for a complete understanding.

  • #31
gonegahgah said:
Lol. Makes for amusing reading :)

Don't grasp your physics too firmly or it might pop your eyes out!

Is that getting closer?

HA!

I've got it! :) Thanks for your patience gonegahgah. You've been more than generous with it.

And thank you too Kotex. I may be goofing around with you because you came off so arrogant with your "puking entrance", but in fairness to you, it is obvious that you know a lot about balls.

Seriously, though I totally understand everything that's been explained to me here and I'm grateful to be allowed to sputter layman's questions and receive expertly tutored answers.
 

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