Just how strong is the Air pressure

[AshUchiha]

What ARE you talking about? Do you mean swimming pools that are used to train astronauts? They are just swimming pools. The spacesuits are set to provide neutral buoyancy, but gravity is still there. Buoyancy and gravity are not the same thing.

Exactly sir!, I see, so is it impossible to have "zero gravity"?

 

[rootone]

I see, I've heard there are "chambers" which have very less gravity{which can make us float in that object"} I would like to know how it achieved?

You might be thinking of aircraft which are sometimes used to simulate weightlessness.
The plane goes into a steep dive calculated such that occupants are in free fall towards the earth, effectively making them weightless.
This can only be done for a short period of time because the plane has to end the dive, at this point the occupants pay for the weightlessness by experiencing 2 or 3 times their normal weight.

 

[phinds]

Exactly sir!, I see, so is it impossible to have "zero gravity"?

I'm not sure if you are confusing zero gravity with weightlessness. You can, as rootone pointed out, have weightlessness in a gravitational field if you are in free fall.

 

[AshUchiha]

Weightlessness is almost impossible?? Mass can neither be created nor be destroyed, and our Earth's gravity hasn't replenished, so we are facing gravity always {While on Earth}, And as

Weight= Mass+Gravity, one which cannot be destroyed and one which is always present. So I wonder how can we counter these and attain weightlessness?

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

 

[phinds]

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

No, it is exactly weightlessness.

 

[virgil1612]

Weightlessness is almost impossible?? Mass can neither be created nor be destroyed, and our Earth's gravity hasn't replenished, so we are facing gravity always {While on Earth}, And as

Weight= Mass+Gravity, one which cannot be destroyed and one which is always present. So I wonder how can we counter these and attain weightlessness?

Also Free fall towards Earth, would increase our Acceleration due to g, so gravity is acting on us. So what you might be explaining would be just "near" to weightlessness ?

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

 

[phinds]

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

No, being in a pool is not weightless, nor does it feel so. Float on your back in a pool sometime an lift your arm up. It will not feel weightless at all, whereas if you are in orbit, you really are weightless. As I said previously, being in a pool can provide neutral buoyancy but not weightlessness.

 

[virgil1612]

No, being in a pool is not weightless, nor does it feel so. Float on your back in a pool sometime an lift your arm up. It will not feel weightless at all, whereas if you are in orbit, you really are weightless. As I said previously, being in a pool can provide neutral buoyancy but not weightlessness.

Well, of course it's not exact weightlessness. But it's pretty close. And about lifting the arm, I was mentioning that you should be "completely submerged". But of course it's not the real thing. But hey, it's good enough for the astronauts!

 

[AshUchiha]

But weight is the addition of mass and gravity , so I must include it right?. I guess by weightlessness you mean having no opposing force on us preventing us from falling to the core of the Earth. Is that what you meant by that?

 

[AshUchiha]

You are weightless (notice that no one is saying massless) if you don't feel the floor under your feet. This is happening if you are in an elevator or aircraft that are in free fall, if you are completely submerged in a pool, etc. It is exactly the same thing as if you would orbit the Earth in a satellite.

So I was right, but it can't be called weightlessness, I would rather recommend naming it "feel as if weightless"

 

[virgil1612]

So I was right, but it can't be called weightlessness, I would rather recommend naming it "feel as if weightless"

In Physics books they are talking about 'real weight' and 'apparent weight'. The real weight is mg, so for this to be zero you would need be to somewhere far from any celestial objects (in fact this is never zero), so it wouldn't be practical. The 'apparent weight' is defined as the normal force N, which is the interaction force between your feet and the floor. This force can be zero (or almost zero in the case of the pool) in the situations described in a previous post. It is in connection with the 'apparent weight' that the term 'weightlessness' is defined and used.

 

[AshUchiha]

In Physics books they are talking about 'real weight' and 'apparent weight'. The real weight is mg, so for this to be zero you would need be to somewhere far from any celestial objects (in fact this is never zero), so it wouldn't be practical. The 'apparent weight' is defined as the normal force N, which is the interaction force between your feet and the floor. This force can be zero (or almost zero in the case of the pool) in the situations described in a previous post. It is in connection with the 'apparent weight' that the term 'weightlessness' is defined and used.

Oh my god! I've been studying Weight as the summation of Mass and gravity, and not Mass times gravity!.I'm soo sorry virgil .
Tell me this, would I feel acceleration due to gravity if I put my feet above from ground for like, say 1/2 second. The accel. due to gravity is 9.8m/s^2. So its for 1 second right?. So what about when my feet is half second to upward to reach the ground?. Would it be the half of 9.8m/s^2

 

[phinds]

Oh my god! I've been studying Weight as the summation of Mass and gravity, and not Mass times gravity!.I'm soo sorry virgil .
Tell me this, would I feel acceleration due to gravity if I put my feet above from ground for like, say 1/2 second. The accel. due to gravity is 9.8m/s^2. So its for 1 second right?. So what about when my feet is half second to upward to reach the ground?. Would it be the half of 9.8m/s^2

When you jump up such that your body is completely off the ground, you are weightless until you touch down again. You are being acted on by gravity but you have no weight, exactly as though you were in orbit. This is what I was trying to get you to understand earlier.

 

[AshUchiha]

True , thanks sir. Though the velocity we will fall would be different due to the different mass . And what about my accel. due to gravity question??

 

[Nugatory]

Though the velocity we will fall would be different due to the different mass

No. The velocity of a falling object is independent of the mass. This is a FAQ up in the "STEM Learning Materials" section of this forum.

This thread has drifted far from its original topic, and there is little point in continuing the random walk approach to learning physics. Instead, I suggest that you work on acquiring a clear sense of what is meant by "mass", "weight", "speed", "velocity", "force", and "acceleration" and the mathematical relationships between them. Until you've built this foundation (which we can help you with) you will find it very difficult to make sense of anything here.