# How would the UA explain this?

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#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #30 on: December 16, 2009, 03:52:04 PM »
Mass doesn't have much to do with air resistance, anyway. It's more about surface area.

My god... you're right.

Aha!! You caught me on that one. I was hoping you would miss it. I really meant that the hammer has more mass for the air to resist. My mistake.

Oh, sorry about that. I had assumed you understood how air resistance works.

And I do.

So you have changed your explanation twice in this very thread... both to wrong statements...

Perhaps you could point out the mass term of the moving object in the equation for determining drag for him then.
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

?

#### Mookie89

• 1327
• Artilles is a goddess
##### Re: How would the UA explain this?
« Reply #31 on: December 16, 2009, 05:09:33 PM »
The point of my post is, what force would cause the water bottle to stop spinning so suddenly? If there is no such thing as gravity, then what makes the bottle and hammer stop spinning?

Something is obviously stopping the inertial spinning motion of the bottle of water and hammer, so what force (in the UA model) causes this?
Quote from: Tom Bishop
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#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #32 on: December 16, 2009, 05:29:20 PM »
The point of my post is, what force would cause the water bottle to stop spinning so suddenly? If there is no such thing as gravity, then what makes the bottle and hammer stop spinning?

Something is obviously stopping the inertial spinning motion of the bottle of water and hammer, so what force (in the UA model) causes this?

What force would cause the hammer to stop spinning not in a UA model?
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

?

#### Mookie89

• 1327
• Artilles is a goddess
##### Re: How would the UA explain this?
« Reply #33 on: December 16, 2009, 05:33:18 PM »
The point of my post is, what force would cause the water bottle to stop spinning so suddenly? If there is no such thing as gravity, then what makes the bottle and hammer stop spinning?

Something is obviously stopping the inertial spinning motion of the bottle of water and hammer, so what force (in the UA model) causes this?

What force would cause the hammer to stop spinning not in a UA model?

You mean what force causes the water bottle/hammer to stop spinning in the RE model?

Well, it's the force of gravity overcoming the force of inertia. An object that's in motion tends to stay in motion, unless acted upon by an outside force.

So unless there is a force stopping the spin of the bottle/hammer, it will keep spinning.
« Last Edit: December 16, 2009, 05:37:22 PM by Mookie89 »
Quote from: Tom Bishop
Ugh ugh! Ugh nug nug ugh!

It's fourteen French social dances past the hour.

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #34 on: December 16, 2009, 05:49:00 PM »
The point of my post is, what force would cause the water bottle to stop spinning so suddenly? If there is no such thing as gravity, then what makes the bottle and hammer stop spinning?

Something is obviously stopping the inertial spinning motion of the bottle of water and hammer, so what force (in the UA model) causes this?

What force would cause the hammer to stop spinning not in a UA model?

You mean what force causes the water bottle/hammer to stop spinning in the RE model?

Well, it's the force of gravity overcoming the force of inertia. An object that's in motion tends to stay in motion, unless acted upon by an outside force.

So unless there is a force stopping the spin of the bottle/hammer, it will keep spinning.

Think about what point on the hammer the rotation happens about and what point gravity acts upon.
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

?

#### Mookie89

• 1327
• Artilles is a goddess
##### Re: How would the UA explain this?
« Reply #35 on: December 16, 2009, 05:55:02 PM »
The point of my post is, what force would cause the water bottle to stop spinning so suddenly? If there is no such thing as gravity, then what makes the bottle and hammer stop spinning?

Something is obviously stopping the inertial spinning motion of the bottle of water and hammer, so what force (in the UA model) causes this?

What force would cause the hammer to stop spinning not in a UA model?

You mean what force causes the water bottle/hammer to stop spinning in the RE model?

Well, it's the force of gravity overcoming the force of inertia. An object that's in motion tends to stay in motion, unless acted upon by an outside force.

So unless there is a force stopping the spin of the bottle/hammer, it will keep spinning.

Think about what point on the hammer the rotation happens about and what point gravity acts upon.

The point of rotation happens at the center of the frame of the hammer, and gravity acts on the whole hammer itself. I'm not sure where you're going with this, I think I have an idea.
Quote from: Tom Bishop
Ugh ugh! Ugh nug nug ugh!

It's fourteen French social dances past the hour.

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #36 on: December 17, 2009, 08:57:44 AM »
The point of rotation happens at the center of the frame of the hammer, and gravity acts on the whole hammer itself. I'm not sure where you're going with this, I think I have an idea.

I got a bit busy here and it took a while to find a good animation to show.

In This link set the value of m1/m2 to the lowest value 0.1.  This will represent your hammer being thrown.  It should default to tracing the path of both masses and of the mass center of the system.  Notice how the angular motion of the system stays constant throughout the path and that the mass center travels on an a curve due to the influence of gravity.  This path is governed by the equations of motion of a particle, which the cm can be modeled as.  The range of the body is determined by the angle it is fired on, the initial velocity (both of which can be changed here) and the acceleration on the cm due to gravity via Vo2/g * sin(2Thetao). Notice that as the term g were taken to 0(as in the case of an accelerating earth) the range would tend to infinity and the object's cm would travel on a straight line. Once the object becomes a projectile (it leaves your hand) there is no accleration on it and it's distance from earth would increase/decrease in the same manner as if it were under the influence of gravity.  The difference would be that the earth would move up to and catch the hammer, where as in the accepted model the hammer falls back to Earth.

This animation does not consider air resistance.  In the case of the hammer being thrown look at the area on each side of the center of mass of the hammer.  Each side of the center of rotation has an equal mass, but an unequal surface area.  The drag experienced by the hammer would then be related to the size of the area presented to the wind and would create a torque about this center of mass.  The drag would then tend to rotate the hammer so that it presented the smallest face to the wind.

Here is another model illustrating the same concept.

The most important thing to note is that this in no way proves the earth to be flat.

"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

• 997
##### Re: How would the UA explain this?
« Reply #37 on: December 17, 2009, 02:50:00 PM »
Heavier objects do fall faster on earth than light ones, but it's not because of gravity. Gravitational acceleration remains constant for all objects but air resistance causes objects that are more dense to fall faster. To exemplify this drop a piece of paper and a book. The book will fall faster.

My understanding of physics doesn't go much further than this, but under the flat earth model "gravity" is caused by the upward acceleration of the Earth. The fact that time slows down when objects accelerate notwithstanding, we can imagine this system in the context of a giant floating sphere filled with air in a zero gravity environment (bear with me as I try to wrap my head around this).

If in this giant sphere somebody started spinning a water bottle that is not full, would it not continue to spin the same way as a bottle roughly the same weight that is full?

If I accelerated a surface (imagine a table, symbolizing the Earth) towards the bottles would it have any effect?

Somebody needs to explain to me how gravity works. if I'm wrong here I'm not surprised, but if I'm right the entire FET of gravity is debunked.

" class="bbc_link" target="_blank" rel="noopener noreferrer">

Water does not behave like this on planet Earth. Rain droplets are not spheres, they are shaped like, well, rain drops. The Flat Earth Theory suggests that if I accelerated a flat surface towards these water droplets they would change shape. Are we going to now hear the Flat Earthers suggest that water droplets are in on the conspiracy as well?
There is evidence for a NASA conspiracy. Please search.

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #38 on: December 17, 2009, 03:16:05 PM »
Heavier objects do fall faster on earth than light ones, but it's not because of gravity. Gravitational acceleration remains constant for all objects but air resistance causes objects that are more dense to fall faster. To exemplify this drop a piece of paper and a book. The book will fall faster.

My understanding of physics doesn't go much further than this, but under the flat earth model "gravity" is caused by the upward acceleration of the Earth. The fact that time slows down when objects accelerate notwithstanding, we can imagine this system in the context of a giant floating sphere filled with air in a zero gravity environment (bear with me as I try to wrap my head around this).

If in this giant sphere somebody started spinning a water bottle that is not full, would it not continue to spin the same way as a bottle roughly the same weight that is full?

If I accelerated a surface (imagine a table, symbolizing the Earth) towards the bottles would it have any effect?

Somebody needs to explain to me how gravity works. if I'm wrong here I'm not surprised, but if I'm right the entire FET of gravity is debunked.

" class="bbc_link" target="_blank" rel="noopener noreferrer">

Water does not behave like this on planet Earth. Rain droplets are not spheres, they are shaped like, well, rain drops. The Flat Earth Theory suggests that if I accelerated a flat surface towards these water droplets they would change shape. Are we going to now hear the Flat Earthers suggest that water droplets are in on the conspiracy as well?

The water bottle would spin in the same way full or empty if it spins about an axis of symmetry (through the top and out the bottom) as the mass distribution would be the same about the axis of rotation (neglecting obviously that the water at the top where the bottle narrows would be distributed differently).
Being that spinning about a non axis of symmetry would get hairy as the water would not be a rigid body in a slightly empty bottle I would imagine the motions would be quite different. As far as in an air filled sphere the bottle would transfer some of its momentum to particles of air.

The raindrops are shaped due to atmospheric drag, which FE would claim is a result of the air, driven by the earth, rushing past the water drop and flattening the front edge that is passing through the gas.  If there were no atmosphere the drop would be perfectly spherical as that is the state of lowest energy.  Though for small drops the shape is actually almost a perfect sphere.  The larger the drop the faster it falls and the flatter the bottom, until eventually the drop is sheared by the force of the air.  If you have access to even a second story window that you can pour a cup of water out quickly, you can try it and watch how the large "drop" will turn into a thin sheet in a mushroom or parachute shape.

Though through all of this, Earth still is spherical.
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

#### Johannes

• Flat Earth Editor
• 2755
##### Re: How would the UA explain this?
« Reply #39 on: December 17, 2009, 03:59:07 PM »

Though through all of this, Earth still is spherical.
Reasoning?

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#### Obama Llama

• 79
##### Re: How would the UA explain this?
« Reply #40 on: December 17, 2009, 04:27:31 PM »

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #41 on: December 17, 2009, 04:46:09 PM »
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

• 997
##### Re: How would the UA explain this?
« Reply #42 on: December 17, 2009, 07:08:54 PM »
Heavier objects do fall faster on earth than light ones, but it's not because of gravity. Gravitational acceleration remains constant for all objects but air resistance causes objects that are more dense to fall faster. To exemplify this drop a piece of paper and a book. The book will fall faster.

My understanding of physics doesn't go much further than this, but under the flat earth model "gravity" is caused by the upward acceleration of the Earth. The fact that time slows down when objects accelerate notwithstanding, we can imagine this system in the context of a giant floating sphere filled with air in a zero gravity environment (bear with me as I try to wrap my head around this).

If in this giant sphere somebody started spinning a water bottle that is not full, would it not continue to spin the same way as a bottle roughly the same weight that is full?

If I accelerated a surface (imagine a table, symbolizing the Earth) towards the bottles would it have any effect?

Somebody needs to explain to me how gravity works. if I'm wrong here I'm not surprised, but if I'm right the entire FET of gravity is debunked.

" class="bbc_link" target="_blank" rel="noopener noreferrer">

Water does not behave like this on planet Earth. Rain droplets are not spheres, they are shaped like, well, rain drops. The Flat Earth Theory suggests that if I accelerated a flat surface towards these water droplets they would change shape. Are we going to now hear the Flat Earthers suggest that water droplets are in on the conspiracy as well?

The water bottle would spin in the same way full or empty if it spins about an axis of symmetry (through the top and out the bottom) as the mass distribution would be the same about the axis of rotation (neglecting obviously that the water at the top where the bottle narrows would be distributed differently).
Being that spinning about a non axis of symmetry would get hairy as the water would not be a rigid body in a slightly empty bottle I would imagine the motions would be quite different. As far as in an air filled sphere the bottle would transfer some of its momentum to particles of air.

The raindrops are shaped due to atmospheric drag, which FE would claim is a result of the air, driven by the earth, rushing past the water drop and flattening the front edge that is passing through the gas.  If there were no atmosphere the drop would be perfectly spherical as that is the state of lowest energy.  Though for small drops the shape is actually almost a perfect sphere.  The larger the drop the faster it falls and the flatter the bottom, until eventually the drop is sheared by the force of the air.  If you have access to even a second story window that you can pour a cup of water out quickly, you can try it and watch how the large "drop" will turn into a thin sheet in a mushroom or parachute shape.

Though through all of this, Earth still is spherical.

But in the absence of gravity the Flat Earth cannot have an atmosphere. It would slide off and dissipate.
There is evidence for a NASA conspiracy. Please search.

?

#### Obama Llama

• 79
##### Re: How would the UA explain this?
« Reply #43 on: December 17, 2009, 07:21:01 PM »
Yeah, but the FEers get to force us to assume that all the other inconsistencies of FE don't exist when discussing a single one.

That's probably a big part of how they convince themselves they actually have an explanation.

• 997
##### Re: How would the UA explain this?
« Reply #44 on: December 17, 2009, 07:30:58 PM »
Yeah, but the FEers get to force us to assume that all the other inconsistencies of FE don't exist when discussing a single one.

That's probably a big part of how they convince themselves they actually have an explanation.

How 'bout that...

I wish my profs were so merciful. I guess academia has a different approach to reaching conclusions, one in which inherent contradictions have no place.
There is evidence for a NASA conspiracy. Please search.

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#### crumblecrumple

• 10
##### Re: How would the UA explain this?
« Reply #45 on: December 18, 2009, 01:07:02 AM »
Toss a hammer into the air? What end comes down first 9 out of 10 times? The head of the hammer, because it is heavier.

Grab a bottle of water that is only about a quarter full by it's top (where the cap is screwed on), now lightly toss it into the air by spinning it upwards. Why does the bottle of water only spin 180 degrees and then stop spinning before it hits the ground? Because of gravity pulling the water down inside the bottle and stopping the spinning motion.

In the UA model, the water bottle and hammer would simply keep spinning at the same rate until the Earth "caught up to it". What would the explanation be for this in the FE model where there would be no gravity in order to cause this effect?

Yeah, this doesn't work.  The way to argue this one (essentially the way to get around the equivalence principle) is to work off fine observations of gravity.  Basically, gravity varies (in a very predictable way) across the earth.  And there are gravimeters that measure this, and gajillions of studies using these gravimeters.  So like if youre close to a big mountain a gravimeter will pick it up.  If I'm remembering this correctly, the first time this was noticed was when some british dudes were doing a survey of India and they noticed that the mass of the himalayas deflected the plumb bobs and introduced non-negligible errors into the survey, or something.

Anyway, the variation of gravity is the right way to argue this.

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #46 on: December 18, 2009, 05:05:59 AM »
Toss a hammer into the air? What end comes down first 9 out of 10 times? The head of the hammer, because it is heavier.

Grab a bottle of water that is only about a quarter full by it's top (where the cap is screwed on), now lightly toss it into the air by spinning it upwards. Why does the bottle of water only spin 180 degrees and then stop spinning before it hits the ground? Because of gravity pulling the water down inside the bottle and stopping the spinning motion.

In the UA model, the water bottle and hammer would simply keep spinning at the same rate until the Earth "caught up to it". What would the explanation be for this in the FE model where there would be no gravity in order to cause this effect?

Yeah, this doesn't work.  The way to argue this one (essentially the way to get around the equivalence principle) is to work off fine observations of gravity.  Basically, gravity varies (in a very predictable way) across the earth.  And there are gravimeters that measure this, and gajillions of studies using these gravimeters.  So like if youre close to a big mountain a gravimeter will pick it up.  If I'm remembering this correctly, the first time this was noticed was when some british dudes were doing a survey of India and they noticed that the mass of the himalayas deflected the plumb bobs and introduced non-negligible errors into the survey, or something.

Anyway, the variation of gravity is the right way to argue this.

They've got some garbage along the lines of how the moon causes tidal bulging and this is what causes changes in "apparent gravity" and another one that relates gravity which does exist to local density variations.

The variations in gravity in the Himalayas wouldn't have anything to do with the mountain itself as the influence of the mountain would tend to decrease your weight as the mountain's mass is located farther out from the center of the Earth and would pull you up (slightly).  The increase in gravity would likely have more to do with a local increase in thickness of a dense area of material below the observation as only material closer to the center can pull you downward.

As far as the atmosphere not slipping off; Bishop has some incorrect hypothesis about how pressure works and another one has something about a force field surrounding the earth keeping the atmosphere in.
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

?

#### crumblecrumple

• 10
##### Re: How would the UA explain this?
« Reply #47 on: December 18, 2009, 05:10:48 PM »

They've got some garbage along the lines of how the moon causes tidal bulging and this is what causes changes in "apparent gravity" and another one that relates gravity which does exist to local density variations.

The variations in gravity in the Himalayas wouldn't have anything to do with the mountain itself as the influence of the mountain would tend to decrease your weight as the mountain's mass is located farther out from the center of the Earth and would pull you up (slightly).  The increase in gravity would likely have more to do with a local increase in thickness of a dense area of material below the observation as only material closer to the center can pull you downward.

As far as the atmosphere not slipping off; Bishop has some incorrect hypothesis about how pressure works and another one has something about a force field surrounding the earth keeping the atmosphere in.

Moon?  Hun.  That's a new one, I think.  I went like >100 posts with Tom about this a long time ago.

Doesn't the ice wall keep that atmosphere in?

#### Its a Sphere

• 1495
##### Re: How would the UA explain this?
« Reply #48 on: December 19, 2009, 08:10:24 AM »

They've got some garbage along the lines of how the moon causes tidal bulging and this is what causes changes in "apparent gravity" and another one that relates gravity which does exist to local density variations.

The variations in gravity in the Himalayas wouldn't have anything to do with the mountain itself as the influence of the mountain would tend to decrease your weight as the mountain's mass is located farther out from the center of the Earth and would pull you up (slightly).  The increase in gravity would likely have more to do with a local increase in thickness of a dense area of material below the observation as only material closer to the center can pull you downward.

As far as the atmosphere not slipping off; Bishop has some incorrect hypothesis about how pressure works and another one has something about a force field surrounding the earth keeping the atmosphere in.

Moon?  Hun.  That's a new one, I think.  I went like >100 posts with Tom about this a long time ago.

Doesn't the ice wall keep that atmosphere in?

It depends.  If something comes up showing how the ice wall couldn't/wouldn't keep the atmosphere in then there is a vector field.

Quote
The Dark Energy Field is a vector field.  It has a gradient that is smallest at the interaction of the atmosphere and the field, called the boundary layer.  The DEF interacts with the magnetic field of the earth at this boundary layer.  These vectors produce a force vector that is orthogonal to the other vectors in four dimensional space.  This force vector is always normal to the boundary layer, thus providing a type of forced containment for the atmosphere.

Itts also in th eFAQ
"We know that the sun is 93 million miles away and takes up 5 degrees of the sky.

#### skeptical scientist

• 1285
• -2 Flamebait
##### Re: How would the UA explain this?
« Reply #49 on: December 20, 2009, 11:44:44 PM »
Neither acceleration (in the UA model) nor gravity (in the RE model) will cause something spinning to stop spinning.

Let's deal with the hammer first. The hammer doesn't stop spinning until it hits the ground (unless you throw it extremely high or don't actually spin it as you throw it). How frequently will we expect the head to hit first? Well, given its high moment of inertia, it should keep spinning at a roughly constant speed until it hits, so all orientations should occur equally often. Since it spins about the center of mass, which is close to the head, and since the head is quite a bit wider than the handle, a larger range of orientations will result in the head hitting first than will result in the handle hitting first. Exact statistics would depend on the hammer in question, but I would guesstimate about 240 degrees of arc result in the head hitting first, and 120 degrees result in the handle hitting first. If the duration of the toss is uniformly distributed, we would expect the head to hit about 2/3 of the time. Of course that won't be the case in practice, but it's probably not too far off. If that is consistent with your findings, then that is consistent with both UA and RE models.

Now let's talk about the water bottle. When you spin the water bottle, you are spinning a very light very thin plastic shell. The water inside, which accounts for most of the mass, does not spin by-and-large, but just sloshes about, and spinning the bottle imparts little angular momentum to the water. Soon after the throw, friction should slow the bottle's spin as much of its angular momentum is transferred through friction to the water inside. The result is that the bottle almost completely stops spinning after a small amount of rotation. Of course, the amount the bottle rotates before this occurs will depend on the relative mass of water and bottle as well as the dynamics of the spin, but one full revolution sounds entirely reasonable. Note that neither gravity nor acceleration appear in this explanation, since the same thing would happen if the bottle were spun in microgravity. The only place FE/RE dynamics come into play is that eventually the earth and bottle will collide due to whatever causes apples to leave trees and end up on the ground.

This obviously shows that Its a Sphere was completely wrong when he predicted that the bottle would spin the same way full or empty, since he is forgetting that a full water bottle is certainly not a rigid body, and its dynamics are much more complex than one.
« Last Edit: December 20, 2009, 11:49:17 PM by skeptical scientist »
-David
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