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Old 3rd May 2019, 11:08 PM   #1641
Robin
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Originally Posted by Gingervytes View Post
No, the opposite force because the water is throwing the ball up. So there should be an equal force down. But the scale does not show that
Some it is maintaining the pressure of the scale, come of it is maintaining the higher water level.

The water does not weigh any more for being displaced.

So if you see any increased weight on the scale when you submerge the ball, that is part of the equal and opposite forc

Are you saying the scale does not register eny more weight when you submerge the ball?
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Old 3rd May 2019, 11:32 PM   #1642
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Originally Posted by Gingervytes View Post
People need to realize that gas expands freely into a vacuum

Does the gas in a rocket exhaust expand freely?
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Old 4th May 2019, 05:24 AM   #1643
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up

https://www.youtube.com/watch?v=JRrvgLVi8Kw

No offense, Jerry, but you're not even trying very hard anymore. That makes me sad.
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Old 4th May 2019, 05:28 AM   #1644
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Originally Posted by Robin View Post
That is right, as the ball moves it moves water molecules out of the way.

Do you agree with that?
Any movement in a fluid displaces it. Even when you walk around
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Old 4th May 2019, 05:30 AM   #1645
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Originally Posted by Robin View Post
Some it is maintaining the pressure of the scale, come of it is maintaining the higher water level.

The water does not weigh any more for being displaced.

So if you see any increased weight on the scale when you submerge the ball, that is part of the equal and opposite forc

Are you saying the scale does not register eny more weight when you submerge the ball?
The initial submersion is building up potential energy. Just like the rocket has to build up pressure
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Old 4th May 2019, 05:31 AM   #1646
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Originally Posted by Gingervytes View Post
Rockets will explode in space.

Does this mean that your answer to this question is “yes”?
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Old 4th May 2019, 06:22 AM   #1647
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up

https://www.youtube.com/watch?v=JRrvgLVi8Kw
Then how do you explain on the rockets that work in space? See, got you there.
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Old 4th May 2019, 06:47 AM   #1648
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Originally Posted by Gingervytes View Post
Just like the rocket has to build up pressure
But you're unwilling to discuss how rockets "build up pressure." You're clinging -- in consummate cargo-cult fashion -- to a small collection of trite mantras like "Gas expands freely into a vacuum" and "There's no reaction force blah blah blah pressure gradient." You can't display even a child's working knowledge of the concepts that apply. Yes, child. We start teaching these concepts in grade 7, when students are around 13 years old.

A thrust chamber can have vacuum outside of it and still severely restrict the mean free path of gas molecules inside it. Vacuum is not some magical kingdom where the kinetic theory of gas suddenly stops governing its behavior. Now in order to quantify this, you need to have much more than a child's understanding. You need to understand systems of vectors, which we've tried to teach you. But you're unwilling to learn, leading most to conclude that you're either hopelessly willingly ignorant, or that you're just having a bit of fun by pretending to be so very obtuse.

The basketball. You arrived at the epiphany that pressure can be thought of as a vector (tensor, really, but we introduce tensors via vectors). We need to go beyond the simple concept of the vector as a simple directed quantity. In order to do that, we have to break you of your misconceptions, such as that of mass flow rate also being a vector because it measures something that moves. Hence the question what is the direction of the pressure contained in a basketball. I was kind enough to compute the magnitude of the pressure for you; now you need to tell us its direction. When you can confidently answer that question, you're ready for the next lesson. Until then, shiling your video and repeating your catch phrases just convinces people that you prefer ignorance and annoyance.
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Old 4th May 2019, 06:48 AM   #1649
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up.
Except that they have been observed to do so, and your unwillingness to acknowledge those observations tends to make people think you're a crackpot.
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Old 4th May 2019, 06:50 AM   #1650
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Originally Posted by Gingervytes View Post
Any movement in a fluid displaces it. Even when you walk around
And every time a fluid is displaced, there is a force that is doing the displacement.

So the fact that the centre of mass goes down means that there has been a force that does this.

So when the ball floats up, there is an equal and opposite force moving the centre of mass of the water down.
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Old 4th May 2019, 07:11 AM   #1651
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Originally Posted by Gingervytes View Post
The initial submersion is building up potential energy. Just like the rocket has to build up pressure
The initial submersion builds up potential energy. The continued force holding the balloon or ball down maintains that potential energy.

The ball is being pushed up by the cumulative force of water molecules against the molecules in the ball. Momentum is always conserved in these collisions.

If there was no equal and opposite force when the water molecules struck the molecules of the ball then the water would freeze in under a second.
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Old 4th May 2019, 08:08 AM   #1652
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Originally Posted by Robin View Post
The initial submersion builds up potential energy. The continued force holding the balloon or ball down maintains that potential energy.

The ball is being pushed up by the cumulative force of water molecules against the molecules in the ball. Momentum is always conserved in these collisions.

If there was no equal and opposite force when the water molecules struck the molecules of the ball then the water would freeze in under a second.
Then why no force observed on the scale?
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Old 4th May 2019, 08:47 AM   #1653
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Originally Posted by Gingervytes View Post
Then why no force observed on the scale?
You're talking about the bit in your video where you have a ball on a stick and push it down into a beaker of water? Can you roughly estimate the change of downward force you should expect to measure between the two static conditions, where the ball is deep in the water and where its near the surface? Once you do that we can check to see if it happens.
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Old 4th May 2019, 08:50 AM   #1654
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up
Zeppelins won't work in America. I tried to tell them. It was obviously impossible because reasons.
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Old 4th May 2019, 09:21 AM   #1655
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Originally Posted by Jack by the hedge View Post
Zeppelins won't work in America. I tried to tell them. It was obviously impossible because reasons.

Perhaps the huge manatee interfered with them in some way.
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Old 4th May 2019, 09:24 AM   #1656
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Originally Posted by Mojo View Post
Perhaps the huge manatee interfered with them in some way.
Did anyone inspect local grassy knolls for large aquatic mammals? That's all I'm saying.
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Old 4th May 2019, 10:45 AM   #1657
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Originally Posted by Gingervytes View Post
Any movement in a fluid displaces it. Even when you walk around
So, you agree that rockets can propel in the vacuum of space.

Why didn’t you say so much earlier?
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Old 4th May 2019, 10:47 AM   #1658
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up

https://www.youtube.com/watch?v=JRrvgLVi8Kw
1. The tank car implosion was from a Mythbusters episode. It was not in space. It was not a rocket. It did not explode. It was not designed or constructed to resist an interior vacuum.
2. The soda can was designed and constructed to remain nominally on the surface of the earth at atmospheric pressure. It was not a rocket. It was not built to resist extremes of pressure differential. The can exploded but the vacuum chamber that contained it did not collapse - explain that.
3. Provide evidence that the rocket was in the vacuum of space when it exploded. Provide evidence that the interior of the rocket was at a pressure significantly higher than the exterior. Provide evidence that the rocket failure was due to pressure difference between the interior and exterior.
4. Provide evidence that your video was not faked. It looks fake to me.
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Old 4th May 2019, 11:03 AM   #1659
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Originally Posted by Steve View Post
Provide evidence that the interior of the rocket was at a pressure significantly higher than the exterior. Provide evidence that the rocket failure was due to pressure difference between the interior and exterior.
One of my interview questions for junior engineering candidates, many years ago, was, "Why don't the space shuttle's tires pop in the vacuum of space?" You get a variety of answers, all reasonably considered. But the real answer is that the shuttle tires are pressurized to some 300 psi, against which the 14.7 psi of atmospheric pressure is merely marginal. Similarly tank pressures in launch vehicles routinely exceed many atmospheres. The reduction of external pressure due to altitude is, again, marginal in the actual design parameters. When rockets fail, it is almost never due to the effects of vacuum.

Gingervytes seems to approach the notion of ambient pressure with this wide-eyed wonder -- or maybe wide-eyed fear. He is utterly unconversant with the actual quantities involved. His presentation is entirely innumerate. He displays no proper qualitative understanding of Bernoulli's kinetic theory of gases and no proficiency in the mathematical concepts and techniques that pertain to his proof. Unfortunately he argues as if everyone labors under the same deficiencies and misconceptions as he.
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Old 4th May 2019, 12:03 PM   #1660
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Originally Posted by Gingervytes View Post
Then why no force observed on the scale?
Because we only see it while the float is fully submerged. Moving it up and down does not change the buoyancy.

What will happen if you do it is as follows:

1) Float above water: Scale will read weight of vessel plus water.

2) Float floating on water: Scale will read weight of vessel plus water plus float.

3) Float pressed under water: Scale will read weight of vessel plus water plus total mass of water displaced by float.

- The position of the float in the water column will not show on the scale as this is a matter of internal pressures in the system. The video only shows different positions of the float fully submerged, which shows that it is fraudulent. The experimenters cannot have missed what happened when they inserted the float in the water, so they are deliberately suppressing this information to make their false point.

Hans
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Old 4th May 2019, 12:06 PM   #1661
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Originally Posted by Jack by the hedge View Post
You're talking about the bit in your video where you have a ball on a stick and push it down into a beaker of water? Can you roughly estimate the change of downward force you should expect to measure between the two static conditions, where the ball is deep in the water and where its near the surface? Once you do that we can check to see if it happens.
There will be no outside difference. Since water is not compressible, the buoyancy of the float is the same, no matter where in the water column it is placed: It will always be equal to the weight of the displaced water.

Hans
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Old 4th May 2019, 12:11 PM   #1662
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Originally Posted by Robin View Post
The initial submersion builds up potential energy. The continued force holding the balloon or ball down maintains that potential energy.

The ball is being pushed up by the cumulative force of water molecules against the molecules in the ball. Momentum is always conserved in these collisions.

If there was no equal and opposite force when the water molecules struck the molecules of the ball then the water would freeze in under a second.
Ehrm ... at best irrelevant.

The float is only ever pushed up with a force equal to the weight of the water it replaces.

If it floats freely, this will be equal to the mass of the float.
It it is pressed into the water it will be equal to the mass of the water now replaced.

Whatever force is pressing up on the float will register on the scale.

Moving it up and down while fully submerged will only cause temporary inertial changes as water flows around it.

Hans
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Old 4th May 2019, 01:41 PM   #1663
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Originally Posted by phunk View Post
Originally Posted by Gingervytes View Post
I substituted velocity for exit velocity. Both are vectors, not scalar.

So let’s say I travel at constant velocity for 10 seconds and travel 10 meters. My velocity is 1 m/s.

So if I say acceleration =v/t (the units match), my acceleration would be 1/10 m/s^2.

We obviously know that this is not correct because your velocity was constant. The units match but the equation didn’t represent reality. Now if I use change in velocity instead of just velocity, the equation works.
Acceleration isn't v/t. it's dv/dt. So your units don't match and you plugged in the wrong numbers.

I've not been following this thread, but that's a beautifully idiotic catch there.
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Old 4th May 2019, 01:57 PM   #1664
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Originally Posted by jimbob View Post
I've not been following this thread, but that's a beautifully idiotic catch there.
Unfortunately it's not quite right though since the units do match.
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Old 4th May 2019, 02:07 PM   #1665
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This guy still trolling??
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Old 4th May 2019, 02:27 PM   #1666
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Originally Posted by RecoveringYuppy View Post
Unfortunately it's not quite right though since the units do match.
True, but it's still an idiotic statement. If I say acceleration is Chedder/Parmesan, and is dimensionless with respect to cheese, the units might match but as far as I am aware, that might be the most meaningless statement in this thread.

If I say acceleration is Width/Length, and is dimensionless, the units match, but it still is wrong.
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Old 4th May 2019, 02:33 PM   #1667
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Originally Posted by Norman Alexander View Post
This guy still trolling??
Obviously.
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Old 4th May 2019, 02:46 PM   #1668
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Originally Posted by MRC_Hans View Post
Because we only see it while the float is fully submerged. Moving it up and down does not change the buoyancy.

What will happen if you do it is as follows:

1) Float above water: Scale will read weight of vessel plus water.

2) Float floating on water: Scale will read weight of vessel plus water plus float.

3) Float pressed under water: Scale will read weight of vessel plus water plus total mass of water displaced by float.

- The position of the float in the water column will not show on the scale as this is a matter of internal pressures in the system. The video only shows different positions of the float fully submerged, which shows that it is fraudulent. The experimenters cannot have missed what happened when they inserted the float in the water, so they are deliberately suppressing this information to make their false point.

Hans
As soon as the ball is let go the scale reading decreases even when the container is duly Submerged in the water
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Old 4th May 2019, 03:16 PM   #1669
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Originally Posted by Gingervytes View Post
As soon as the ball is let go the scale reading decreases even when the container is duly Submerged in the water
Because you're pushing down on the container?
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Old 4th May 2019, 03:46 PM   #1670
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Originally Posted by Gingervytes View Post
Rockets will explode in space. No chance they go very high up

https://www.youtube.com/watch?v=JRrvgLVi8Kw
Oh Lord give me strength. Tanker cars aren't designed to withstand a vacuum. Soda cans aren't designed to withhold the pressure of the CO2 gas once external ambient atmospheric pressure is eliminated. Oh, and they have very thin aluminum walls.. That didn't occur to you? Why in the world would think rockets would not be designed to withstand a vacuum? One more thing you ignore.; rockets are extremely complicated machines and are known to exploded even when sitting on the launch pad at atmospheric pressure.
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Old 4th May 2019, 06:21 PM   #1671
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Originally Posted by Steve View Post
1. The tank car implosion was from a Mythbusters episode. It was not in space. It was not a rocket. It did not explode. It was not designed or constructed to resist an interior vacuum.

What myth were they busting? (I'm guessing it wasn't the "myth" of rockets in space.)
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Old 4th May 2019, 07:39 PM   #1672
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Originally Posted by Meadmaker View Post
What myth were they busting? (I'm guessing it wasn't the "myth" of rockets in space.)
They were testing if a tank can implode if it is being emptied while air is not being let in. Predictable result ;-).
A friend of mine was a project manager of the construction of the Czech nuclear power station. He told me about a few hiccups they had there. On of the biggest was destroying a huge (I think 1/2 a million l) stainless steel tank for heavy water. They were doing a pressure test on it. Standard protocol - fill with water, pressurise it, check for leaks, pump the water out. All went well, except they didn't open vents enough at the final step and the multi-million $ tank went pancake... Not much pressure, just applied at the wrong direction.
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Old 4th May 2019, 08:18 PM   #1673
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Originally Posted by Elagabalus View Post
Because you're pushing down on the container?
Pushing down is to counteract the force of buoyancy. If there was an opposite force l, the scale reading shouldn’t go down as soon as I release it and it is still submerged in the water
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Old 4th May 2019, 08:21 PM   #1674
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But what pressurized container can hold in the vacuum of space?
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Old 4th May 2019, 08:24 PM   #1675
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Originally Posted by Jack by the hedge View Post
You're talking about the bit in your video where you have a ball on a stick and push it down into a beaker of water? Can you roughly estimate the change of downward force you should expect to measure between the two static conditions, where the ball is deep in the water and where its near the surface? Once you do that we can check to see if it happens.
Yess you can see it on the scale. You might have to slow down the video to see. But the difference is approx 100 grams
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Old 4th May 2019, 08:38 PM   #1676
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Originally Posted by Robin View Post
Some it is maintaining the pressure of the scale, come of it is maintaining the higher water level.

The water does not weigh any more for being displaced.

So if you see any increased weight on the scale when you submerge the ball, that is part of the equal and opposite forc

Are you saying the scale does not register eny more weight when you submerge the ball?
No I’m saying there is no observable opposite force when the ball accelerates
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Old 4th May 2019, 08:45 PM   #1677
JayUtah
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Originally Posted by Gingervytes View Post
But what pressurized container can hold in the vacuum of space?
The ones I told you about. The "vacuum of space" is a measly 15 psi from sea level. Ordinary hydraulic lines, for example, are good for 3,500 psi and beyond. You really have no intuitive understanding of what you're talking about.
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Old 4th May 2019, 08:47 PM   #1678
Robin
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Originally Posted by Gingervytes View Post
Then why no force observed on the scale?
As I said, you need to describe the experiment in your own words and say what you think it proves.

How much weight do you expect to see and why?

The scale is measuring the pressure on the bottom of the container, ie the sum of the forces of the water molecules hitting the molecules in the glass.

The ball is being pushed up by the net force of the water molecules colliding with the molecules in the ball. The equal and opposite for is translated into the new momentum of the water molecule as it bounces back.

If it did not bounce back with an equal force, if it just stopped dead, then the water would freeze in a split second.

So the water molecule bounces back with momentum conserved and it has tog be transmitted to the rest of the water, not necessarily in a down direction initially.

Think of a cue ball hitting a group of billiard balls, not all of them scatter in the same direction.

Basically what you have when you release the ball is a lot of turbulence with forces going every which way.
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Old 4th May 2019, 09:14 PM   #1679
bruto
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Originally Posted by Gingervytes View Post
But what pressurized container can hold in the vacuum of space?
It's too bad. It would have been so handy, for example to be able to design a double walled glass bottle with a vacuum inside. If only it did not shatter into a million pieces under atmospheric pressure, we'd be able to keep our soup and coffee warm on the road. Too bad.
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Old 5th May 2019, 01:45 AM   #1680
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Originally Posted by Gingervytes View Post
As soon as the ball is let go the scale reading decreases even when the container is duly Submerged in the water
If the float is left to float freely, the push in the scale is less than if it is pushed under the water, yes. Just like I explained above.

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