Does gravity stop accelerating objects once they are in contact with

AI Thread Summary
Gravity continues to act on objects even when they are in contact with the Earth's surface, but the normal force exerted by the ground counteracts this gravitational force. When an object is at rest on a flat surface, the net force is zero, resulting in no acceleration according to Newton's second law. Human bodies are adapted to handle the constant forces of gravity and normal force, which is why we don't feel "squashed." Additionally, atmospheric pressure, despite being significant, is not felt due to our body's acclimatization. As people age, they may become more aware of gravity's effects on their bodies, leading to discussions about physical changes over time.
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 alot?
 


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 alot?

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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