Does gravity stop accelerating objects once they are in contact with

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Discussion Overview

The discussion revolves around whether gravity stops accelerating objects once they are in contact with the Earth's surface, exploring the implications of forces such as the normal force and the effects of gravity on the human body.

Discussion Character

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

Main Points Raised

  • Some participants propose that once an object hits the ground, the normal force exerted by the ground opposes gravity, resulting in a net force of zero and thus zero acceleration, according to Newton's second law.
  • Others question why people are not significantly affected by the opposing forces of gravity and normal force, suggesting it may be due to gravity being a relatively weak force.
  • Some participants argue that human bodies are adapted to withstand these forces, indicating that we do not "feel squashed" because we have lived with these forces since birth.
  • A later reply humorously suggests that aging may increase the effects of gravity on the body, leading to a greater attraction to the ground.
  • There are light-hearted comments about the implications of aging and gravity, including jokes about turning into a black hole.

Areas of Agreement / Disagreement

Participants express a mix of curiosity and humor regarding the effects of gravity and normal force, with some agreement on the basic mechanics but no consensus on the broader implications for human experience or aging.

Contextual Notes

The discussion includes assumptions about the nature of forces and human physiology, but these are not fully explored or resolved.

DCLawrence00
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Does gravity stop accelerating objects once they are in contact with Earth's surface? If so, why?
 
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DCLawrence00 said:
Does gravity stop accelerating objects once they are in contact with Earth's surface? If so, why?

The Pauli Exclusion principle ?
 


DCLawrence00 said:
Does gravity stop accelerating objects once they are in contact with Earth's surface? If so, why?

Once the object hits the ground, the ground exerts an upward force on the object, called the normal force.

In the case where the object falls on a flat part of the Earth (no incline), the normal force directly opposes gravity and is equal, in strength, to the gravitational force.

Therefore, the net force on the object is 0 and by Newton's second law, it's acceleration is also 0.
 


Thanks G01, that makes sense. That leads me to another question. Why aren't people greatly affected (physically) by the force of gravity and normal force acting on them at all times from opposite directions? Is it due to gravity being such a weak force?
 


DCLawrence00 said:
Thanks G01, that makes sense. That leads me to another question. Why aren't people greatly affected (physically) by the force of gravity and normal force acting on them at all times from opposite directions? Is it due to gravity being such a weak force?

This is just because our bodies are built to withstand such forces on a daily basis. Essentially, we don't "feel squashed" because our bodies can handle these forces and we've lived with them since the first day of our lives.

For the same reason, we don't notice the weight of the air in the atmosphere pressing down on us. Even though atmospheric pressure is 14.6psi, we don't notice a huge force pushing down on our heads. Once, again, our bodies are just used to it and built to withstand it.
 


Thanks for your answers, G01!
 


DCLawrence00 said:
Thanks G01, that makes sense. That leads me to another question. Why aren't people greatly affected (physically) by the force of gravity and normal force acting on them at all times from opposite directions? Is it due to gravity being such a weak force?

You must be quite young. The older you get, the more you will see how gravity affects your body.
 


brocks said:
You must be quite young. The older you get, the more you will see how gravity affects your body.

I thought it was a fundamental law of physics that old people had a greater attraction to the ground...isn't that why they like to sit down a lot?
 


It's also why you see those TV commercials for medical-alert devices: "Help, I've fallen and I can't get up!"
 
  • #10


Drakkith said:
I thought it was a fundamental law of physics that old people had a greater attraction to the ground...isn't that why they like to sit down a lot?

I think this is also the reason you shrink as you get older.
 
  • #11


Hrmmm...by this reasoning, if I live long enough I will turn into a Black Hole.
 
  • #12


drakkith said:
hrmmm...by this reasoning, if i live long enough i will turn into a black hole.

lol!
 

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