Weightlessness During Freefall

Really cool experiment.

Terminal velocity is the maximum velocity attainable by an object as it falls through a fluid. It occurs when the sum of the drag force and the buoyancy is equal to the downward force of gravity acting on the object.

Quote from: NotSoSkeptical on January 08, 2023, 06:03:42 PM

Really cool experiment.

Uhhhhhhhh, that's not weightlessness.

If you were actually weightless, wouldn't you be able to stop your fall?

Damn straight you would. Just weightless yourself to a stall in momentum, halt freefall, and stay there or swim gently toward the ground.

But no, you are still falling.

What this is, is terminal velocity. You see, science, real science, doesn't rush to label things incorrectly.

A terminal velocity is when an object reaches the maximum speed it will get.

Quote

Terminal velocity is the maximum velocity attainable by an object as it falls through a fluid. It occurs when the sum of the drag force and the buoyancy is equal to the downward force of gravity acting on the object.

Straight from wikipedia. Now, I would ignore the "downward force of gravity" part and the insistence on fluids. There is no downward force of gravity needed, as objects fall when they are heavier than a fluid (or gas). This is just an aspect of buoyancy: it causes floating when object is lighter than a medium, and the inverse is true. Objects travel through a fluid (or a gas), the object attains its max speed, and buoyancy and drag force are equal.

I haven't really changed anything about the definition of terminal velocity, other than applying it to air (which any parachuter can tell you does happen). Whereas you have called it weightlessness.

Wanna see how weightless people are when they hit the ground with no parachute? Then you've changed a term. They aren't weightless, they have achieved terminal velocity and are in a state of equilibrium. This is a blessing from God, as it means the laws of physics make them only kinda sorta smashed instead of totally ground to powder and mush. What? Aren't you happy that when die from a fall, you're less dead than you could be without a max speed?

Water Doesn’t Leak Out Science Experiment

https://coolscienceexperimentshq.com/water-doesnt-leak/


Gravity is also the reason water doesn’t leak out of the holes when you drop the cup in Step 4. In this step, gravity is still pulling the water back to Earth, but this time the cup and water are falling back to Earth at the same rate when you drop the cup. This doesn’t allow water to leak out of the cup because the water is already taking the path of least resistance back to Earth – straight down with the cup.

I haven't really changed anything about the definition of terminal velocity, other than applying it to air (which any parachuter can tell you does happen). Whereas you have called it weightlessness.

I don't get this objection. Gravity isn't magic. Any downwards acceleration is gonna cause pretty much the same effects, whether it's justified with respect to an alt-buoyancy model, UA, modified gravity, subquark strings... You can, for the purposes of this, model it all pretty much the same. All you need is for water to, as Data's link says, take the path of least resistance down to the Earth. That, like, seems completely in line with everything up to and including Turbo's model?

free fall
noun
1
: the condition of unrestrained motion in a gravitational

https://www.merriam-webster.com/dictionary/free%20fall

I don't get this objection. Gravity isn't magic. Any downwards acceleration is gonna cause pretty much the same effects, whether it's justified with respect to an alt-buoyancy model, UA, modified gravity, subquark strings... You can, for the purposes of this, model it all pretty much the same. All you need is for water to, as Data's link says, take the path of least resistance down to the Earth. That, like, seems completely in line with everything up to and including Turbo's model?

Quote from: Slime on January 09, 2023, 05:56:31 AM

I don't get this objection. Gravity isn't magic. Any downwards acceleration is gonna cause pretty much the same effects, whether it's justified with respect to an alt-buoyancy model, UA, modified gravity, subquark strings... You can, for the purposes of this, model it all pretty much the same. All you need is for water to, as Data's link says, take the path of least resistance down to the Earth. That, like, seems completely in line with everything up to and including Turbo's model?

Hmmm, not sure if I agree. Maybe the question becomes, "Why is there resistance and what is causing the resistance?"

In Turbo's notion, (I think), everything falls because it's returning to its origin, earth.

In the others, I'm just not sure why the water spouts would stop spouting.

Quote from: Stash on January 09, 2023, 06:26:36 AM

Quote from: Slime on January 09, 2023, 05:56:31 AM

I don't get this objection. Gravity isn't magic. Any downwards acceleration is gonna cause pretty much the same effects, whether it's justified with respect to an alt-buoyancy model, UA, modified gravity, subquark strings... You can, for the purposes of this, model it all pretty much the same. All you need is for water to, as Data's link says, take the path of least resistance down to the Earth. That, like, seems completely in line with everything up to and including Turbo's model?

Hmmm, not sure if I agree. Maybe the question becomes, "Why is there resistance and what is causing the resistance?"

In Turbo's notion, (I think), everything falls because it's returning to its origin, earth.

In the others, I'm just not sure why the water spouts would stop spouting.

Honestly I brought up Turbo because, if you grant the premise, it gives the most explicit illustration of why it works - the water is heading right down to the Earth, it just no longer needs to go out the holes to do so. If my understanding is correct, it isn't necessarily that there's resistance to the movement, it's that the downwards force no longer needs to send anything out the holes because the water can go in another direction - so, maybe better to say there is resistance when the container is stationary exerted by the base of the can that as a result pushes the water out the holes, and no resistance when it is falling hence no force out the holes.

In this sort of situation, to me, the best question is "What is the explanation under gravity, and why can it not hold otherwise?"
Beyond Data's circular 'Freefall is defined with reference to gravity,' under FE models I'm not sure I see why this principle would fail.

I'm not clear on the resistance of the base changes when transitioning from stationary to moving when applying Turbo's thing and especially UA.

I can't think of a reason as to why it would stop flowing. In other words, I don't know why the water's needs would actually change, flowing out the holes seems just as good as riding along with the container.

Quote from: Stash on January 09, 2023, 07:34:03 AM

I'm not clear on the resistance of the base changes when transitioning from stationary to moving when applying Turbo's thing and especially UA.

If the base of the container is moving downwards, then necessarily it's exerting less of an upwards force than when it's stationary. The only time I can see that being a problem is with the few 'no reaction force on stationary objects' models that seem to have popped up, but that's a) more an issue with why water goes out the holes in the first place than why it would stop, b) likely resolvable with reference to the properties of liquid.
Like, if we were to keep the can stationary in the air and instead neatly slice off the bottom layer, the water would stop coming out the holes in order to immediately plummet out the bottom. It's taking the only path it can to go down, that's all that's happening in any model. When the container itself is descending, there's an easier path down.

Or, short version: if we accept, for the purposes of discussion, that water wants to go down when it is inside the can, then that is sufficient to explain why water will come out the holes, and why it will stop when the container is dropped. Whether the reason the water stays at the bottom of the can is gravity or buoyancy is irrelevant to the physics of the question.

Quote from: Stash on January 09, 2023, 07:34:03 AM

I can't think of a reason as to why it would stop flowing. In other words, I don't know why the water's needs would actually change, flowing out the holes seems just as good as riding along with the container.

Why do you think it stops flowing under gravity?

Let’s put it this way.  All the other models there is no gravity.  Zero.  Zilch. So by logic, they are already in a state of “weightlessness”.

Quote from: DataOverFlow2022 on January 09, 2023, 08:11:40 AM

Let’s put it this way.  All the other models there is no gravity.  Zero.  Zilch. So by logic, they are already in a state of “weightlessness”.

"FE alternatives for gravity don't work."
"Why?"
"Because they're not gravity."

Sheer genius.

Gravity

https://www.merriam-webster.com/dictionary/gravity

3
a
(1)
: the gravitational attraction of the mass of the earth, the moon, or a planet for bodies at or near its surface
(2)
: a fundamental physical force that is responsible for interactions which occur because of mass between particles, between aggregations of matter (such as stars and planets), and between particles (such as photons) and aggregations of matter, that is 10-39 times the strength of the strong force, and that extends over infinite distances but is dominant over macroscopic distances especially between aggregations of matter
 called also gravitation, gravitational force
 compare ELECTROMAGNETISM sense 2a, STRONG FORCE, WEAK FORCE

weight

https://www.merriam-webster.com/dictionary/weight


6
a
: relative heaviness : MASS
b
: the force with which a body is attracted toward the earth or a celestial body by gravitation and which is equal to the product of the mass and the local gravitational acceleration

So, say in sceptimatic‘a model, what would the definition of gravity, weight, free fall, and weightlessness be?  Would they have any real meaning?

Quote from: DataOverFlow2022 on January 09, 2023, 09:21:18 AM

So, say in sceptimatic‘a model, what would the definition of gravity, weight, free fall, and weightlessness be?  Would they have any real meaning?

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume
Free fall - the condition of unrestrained motion in a denpressure system
Weightlessness - lacking an apparent denpressure push

Stop acting like circular arguments are what we need to resort to. They have a real meaning, you just swap out gravity. Congratulations, you have noticed that FET and RET are not the same thing, do you have an actual point to make?

Quote from: Slime on January 09, 2023, 10:22:33 AM

Quote from: DataOverFlow2022 on January 09, 2023, 09:21:18 AM

So, say in sceptimatic‘a model, what would the definition of gravity, weight, free fall, and weightlessness be?  Would they have any real meaning?

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume
Free fall - the condition of unrestrained motion in a denpressure system
Weightlessness - lacking an apparent denpressure push

Stop acting like circular arguments are what we need to resort to. They have a real meaning, you just swap out gravity. Congratulations, you have noticed that FET and RET are not the same thing, do you have an actual point to make?

Sorry.  No gravity, no weight, and free fall becomes meaningless in terms of weight from gravity.

Quote from: DataOverFlow2022 on January 09, 2023, 10:32:50 AM

Quote from: Slime on January 09, 2023, 10:22:33 AM

Quote from: DataOverFlow2022 on January 09, 2023, 09:21:18 AM

So, say in sceptimatic‘a model, what would the definition of gravity, weight, free fall, and weightlessness be?  Would they have any real meaning?

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume
Free fall - the condition of unrestrained motion in a denpressure system
Weightlessness - lacking an apparent denpressure push

Stop acting like circular arguments are what we need to resort to. They have a real meaning, you just swap out gravity. Congratulations, you have noticed that FET and RET are not the same thing, do you have an actual point to make?

Sorry.  No gravity, no weight, and free fall becomes meaningless in terms of weight from gravity.

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume

Now.  With the dropped container.  Why would the water stop flowing out under denpressure.

With gravity. It makes sense.  The water and bucket fall to earth at the same acceleration and direction.  Taking away the motivation for the water to flow out.

How does denpressure. which has nothing to do with relative acceleration, magically disappear to make the water stop flowing just because the container was dropped.

While both are accelerating to earth due to denpressure,

there is no mechanism for turning off “ denpressure” while falling to earth.

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume

Dude, when you need to just whole-hog replace the argument with 'But FEers don't have a downwards force at all!'

Gravity and denpressure are not interchangeable.

Quote from: DataOverFlow2022 on January 09, 2023, 11:52:57 AM

Gravity and denpressure are not interchangeable.

No. They're not. You also don't understand denpressure.

Okay. Let's slow down then. Let's look at what is actually required. My position is this: the necessary trait for this experiment to function is for comparable accelerations to be imparted to the water and the can.
When stationary, the reaction force from the bottom of the can induced by a downwards acceleration forces the water out the holes. When in freefall, there is no reaction force between the water and the bottom of the can, hence nothing to force it out. Equally, if we were to yank the can down with our hand faster than gravity would pull it, we'd get the opposite - a reaction force exerted by the top of the can on the water that pushes it out the holes.
Hence, as said, all that is required is a force that sees the water drawn down towards the Earth's surface while it is inside the can, that is the same force that accelerates the can down when it is dropped.

Do you agree with this basic description of the physics at play, independent of any model?

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume

Quote from: Slime on January 09, 2023, 11:58:23 AM

Quote from: DataOverFlow2022 on January 09, 2023, 11:52:57 AM

Gravity and denpressure are not interchangeable.

No. They're not. You also don't understand denpressure.

Okay. Let's slow down then. Let's look at what is actually required. My position is this: the necessary trait for this experiment to function is for comparable accelerations to be imparted to the water and the can.
When stationary, the reaction force from the bottom of the can induced by a downwards acceleration forces the water out the holes. When in freefall, there is no reaction force between the water and the bottom of the can, hence nothing to force it out. Equally, if we were to yank the can down with our hand faster than gravity would pull it, we'd get the opposite - a reaction force exerted by the top of the can on the water that pushes it out the holes.
Hence, as said, all that is required is a force that sees the water drawn down towards the Earth's surface while it is inside the can, that is the same force that accelerates the can down when it is dropped.

Do you agree with this basic description of the physics at play, independent of any model?

What does any of the have to do with the Cavendish experiments?

And this?

You

Quote

Gravity - a non-existent thing
Weight - the heaviness of an object, resulting from denpressure, relative to density and volume

Dropping the container didn’t change the volume or density of anything.



So.  Why would the water stop flowing under “denpressure”