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some bloke
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- TL;DR Summary
- How much differently does a body which is floating in a fluid medium experience G-force, if at all?
Hi all,
I am trying to get it straight in my head how the interactions would work with a person (or accelerometer, for simplicity) suspended in a fluid, which is itself in a capsule which is then accelerated. Let's say with a rocket, on a linear track, to avoid any circular motion dynamics.
First scenario - neutral buoyancy. the body in the chamber has the same density as the water in the chamber, so floats freely. The capsule is then accelerated at a sufficient rate for the net acceleration (combination of gravity and acceleration) to equal 2g.
f=ma, so with "a" being doubled, the force on the water would double, as would the force on the body.
= -
so the force due to buoyancy will also double, as this also contains gravity. With fluid being incompressible, the density remains the same, as does the volume.
At this point, I have established that the body remains neutrally buoyant during the acceleration, which for a person would feel akin to weightlessness.
What would a person experience? Would they feel the acceleration, or would they feel only an increase in pressure as the water transfers the force it is experiencing onto them?
My thought on the subject of g-force is that it is not an acceleration which causes injury per se, but the structure of a person and the way in which they experience it - in a car, it's not decelerating rapidly which causes damage when you crash, but the fact that different parts of you do so at different times - your nose accelerates into your face when it collides with the dashboard, which then attempts to accelerate your skull, which tries to accelerate your brain. This difference is what causes your brain to slam into your skull when you stop very quickly. Blood pressure & oxygen starvation aside, is this about accurate?
I think part of my inspiration for this train of thought comes from the helium balloon in a car experiment, where it moves forwards as you accelerate instead of backward. Logically the reverse is true, and if a helium balloon is in a car accident, it won't experience the same g-force as everything else.
Any help you can give on understanding this will be welcomed. It's all purely from a curiosity point of view, I'm not trying to achieve anything except knowledge!
I am trying to get it straight in my head how the interactions would work with a person (or accelerometer, for simplicity) suspended in a fluid, which is itself in a capsule which is then accelerated. Let's say with a rocket, on a linear track, to avoid any circular motion dynamics.
First scenario - neutral buoyancy. the body in the chamber has the same density as the water in the chamber, so floats freely. The capsule is then accelerated at a sufficient rate for the net acceleration (combination of gravity and acceleration) to equal 2g.
f=ma, so with "a" being doubled, the force on the water would double, as would the force on the body.
= | buoyant force | |
= | fluid density | |
= | acceleration due to gravity | |
= | fluid volume |
so the force due to buoyancy will also double, as this also contains gravity. With fluid being incompressible, the density remains the same, as does the volume.
At this point, I have established that the body remains neutrally buoyant during the acceleration, which for a person would feel akin to weightlessness.
What would a person experience? Would they feel the acceleration, or would they feel only an increase in pressure as the water transfers the force it is experiencing onto them?
My thought on the subject of g-force is that it is not an acceleration which causes injury per se, but the structure of a person and the way in which they experience it - in a car, it's not decelerating rapidly which causes damage when you crash, but the fact that different parts of you do so at different times - your nose accelerates into your face when it collides with the dashboard, which then attempts to accelerate your skull, which tries to accelerate your brain. This difference is what causes your brain to slam into your skull when you stop very quickly. Blood pressure & oxygen starvation aside, is this about accurate?
I think part of my inspiration for this train of thought comes from the helium balloon in a car experiment, where it moves forwards as you accelerate instead of backward. Logically the reverse is true, and if a helium balloon is in a car accident, it won't experience the same g-force as everything else.
Any help you can give on understanding this will be welcomed. It's all purely from a curiosity point of view, I'm not trying to achieve anything except knowledge!