[Bored chemist]

Since  he doesn't understand the difference between mass and force, I suspect that trying to do thermodynamics isn't going to go well.

Yes I do, what you don't understand is that mass is an ambiguity of weight.

There is nothing ambiguous about either.
It would be better if you learned what was real, rather tan making up stuff that wasn't.

[guest39538]

Since  he doesn't understand the difference between mass and force, I suspect that trying to do thermodynamics isn't going to go well.

Yes I do, what you don't understand is that mass is an ambiguity of weight.

There is nothing ambiguous about either.
It would be better if you learned what was real, rather tan making up stuff that wasn't.

The force imposed on a set of scales by an object is due to the objects mass.

The objects mass on a set of scales is due to the force.

I miss there being any difference apart from ambiguity .

[evan_au]

Geostationary orbit... What stops the object falling to the ground?

Inertia.

The force of gravity has to act on an object for some time before the path of the object is significantly bent.

If the object is traveling parallel to the surface with enough initial velocity, the force of gravity will bend the path into a circle (or ellipse) which does not intersect the ground. ie it does not fall to the ground.

It also helps if you are above the Earth's atmosphere, as atmospheric drag eventually causes satellites in LEO to fall to the ground. In the case of the ISS, Russia periodically sends up rockets to give the ISS a boost into a higher orbit. 

Isaac Newton came up with a nice analogy - firing a powerful cannon from a high mountain.
See: https://en.wikipedia.org/wiki/Newton%27s_cannonball

[Bored chemist]

The objects mass on a set of scales is due to the force.

And, once again, you show that you would be better off studying than pontificating.
The objects mass is still its mass if it is in free fall and not subject to any net force.
The mass is NOT due to a force.

(BTW, learn to use apostrophes while you are at it.)

[The Spoon]

Might also help to read up on density before invoking quantum anything. Seems to be the standard technique of the woo monger and those who have no understanding of science to stick 'quantum' into a sentence to try and make it sound sciencey.

[evan_au]

The force imposed on a set of scales by an object is due to the objects mass.

A mass in a gravitational field (eg a mass near the surface of the Earth) is subject to a force, as per Newton's gravity.
- The mass will start to accelerate towards the center of the Earth, if unopposed.
- A mass sitting stationary on scales is not accelerating, so the scales must oppose the acceleration by exerting an upwards force on the mass that equals the downwards force of gravity.
- Less obviously (because we can't see it), gravity also exerts a downwards force on the air. Just as well, or Earth would lose its atmosphere, and we would all immediately die!
- Scales measure weight (a force), not mass. What confuses this is that scales are calibrated to display kilograms force, when situated at the Earth's surface.
- There is no confusion in the Imperial system, because the pound (lb) is defined as a force.
- The downwards force on the scales is due to the weight of the mass minus the mass of the air it displaces. This correction is important for accurate mass measurement.
- For a steel mass in air, the difference is too small to make a difference in supermarket scales or kitchen scales.

However, if the scales were measuring the weight in water instead of air, the mass of displaced water has a significant impact on the weight, and must be taken into account.
- And if you were measuring the weight of a cork in water, you would find that the mass of displaced water is greater than the mass of the cork, so the net force of the cork will be negative (ie upwards)

And that is how buoyancy works - if the mass of an object is less than the mass of the displaced fluid, the object floats.

The ancient Greek scientist Archimedes (around 250 BC) came up with a more general description of this, see:
https://en.wikipedia.org/wiki/Archimedes%27_principle

[jeffreyH]

R

Might also help to read up on density before invoking quantum anything. Seems to be the standard technique of the woo monger and those who have no understanding of science to stick 'quantum' into a sentence to try and make it sound sciencey.

Is that the definition of a quantum woo monger?

[Petrochemicals]

Take boyancy and the iss another way, as the station enters the atmosphere because of slowed velocity due to slight drag, it encounters resistance in the air, and decelerates, hopefully to terminal velocity, before it breaks apart. The people in the iss do not know they experience deceleration until being ipacted upon the station walls(relativity), even though they are resusted by the air within a little. The scales when falling in the iss, do not register any weight until they have a force opposite and equal.

Helium does not have a regiserable mass on 5he scales on earth, it floats up and out of the earth, yet its got mass.

(Relativity)


After 500 years really Galleileo ows the church an apology for stating both metal balls fell at the same rate.

[evan_au]

as the (ISS) enters the atmosphere because of slowed velocity due to slight drag, it encounters resistance in the air, and decelerates, hopefully to terminal velocity, before it breaks apart.

I'm afraid that terminal velocity in the upper atmosphere is very high, because the air is so thin.
- Then the satellite, travelling at several kilometers per second turns into a fireball.
- Only a heatshield will protect it, and the ISS doesn't have a heatshield.
- Fortunately, the Soyuz return capsule has a heatshield; in case of an emergency, the astronauts get into the Soyuz, undock, and safely reenter Earth's atmosphere, while the ISS burns up in the upper atmosphere.
- Hopefully, no pieces of the ISS hit populated areas. Parts of the earlier Spacelab landed in the remote Western Australian desert.

The ISS is designed to be as light as possible - the solar panels are designed to be unfolded in free fall, and are only strong enough to withstand the gentle push moving the ISS into a higher orbit. So the solar panels, with their large area and light construction are likely to break off first.

Helium does not have a registerable mass on 5he scales on earth, it floats up and out of the earth, yet its got mass

Accurate mass measurement is best done in a vacuum. In a vacuum, Helium would have a registerable mass.

Another method is to take a helium tank, and weight it when it contains compressed gas, and again when it contains a vacuum.

A less accurate way is to place a weight on kitchen scales (say 100g).
- Then take a "floating" helium balloon, and measure its volume
- sticky-tape the balloon's string to the weight. The weight will now weigh less than 100g. Record the new weight (a).
- puncture the balloon, and lay it on the weight. It will now weigh more than 100g (b)

Take the (negative) weight of the helium = (a) - (b), and add the weight of the air displaced by the balloon (when inflated).
This will give you the mass of the helium in the balloon.

[Colin2B]

After 500 years really Galleileo ows the church an apology for stating both metal balls fell at the same rate.

He owes no apology. Anyone who understands the difference between buoyancy and drag will agree.

PS relativity has nothing to do with it.

[Petrochemicals]

as the (ISS) enters the atmosphere because of slowed velocity due to slight drag, it encounters resistance in the air, and decelerates, hopefully to terminal velocity, before it breaks apart.

I'm afraid that terminal velocity in the upper atmosphere is very high, because the air is so thin.
- Then the satellite, travelling at several kilometers per second turns into a fireball.
- Only a heatshield will protect it, and the ISS doesn't have a heatshield.
- Fortunately, the Soyuz return capsule has a heatshield; in case of an emergency, the astronauts get into the Soyuz, undock, and safely reenter Earth's atmosphere, while the ISS burns up in the upper atmosphere.
- Hopefully, no pieces of the ISS hit populated areas. Parts of the earlier Spacelab landed in the remote Western Australian desert.

The ISS is designed to be as light as possible - the solar panels are designed to be unfolded in free fall, and are only strong enough to withstand the gentle push moving the ISS into a higher orbit. So the solar panels, with their large area and light construction are likely to break off first.

Helium does not have a registerable mass on 5he scales on earth, it floats up and out of the earth, yet its got mass

Accurate mass measurement is best done in a vacuum. In a vacuum, Helium would have a registerable mass.

Another method is to take a helium tank, and weight it when it contains compressed gas, and again when it contains a vacuum.

A less accurate way is to place a weight on kitchen scales (say 100g).
- Then take a "floating" helium balloon, and measure its volume
- sticky-tape the balloon's string to the weight. The weight will now weigh less than 100g. Record the new weight (a).
- puncture the balloon, and lay it on the weight. It will now weigh more than 100g (b)

Take the (negative) weight of the helium = (a) - (b), and add the weight of the air displaced by the balloon (when inflated).
This will give you the mass of the helium in the balloon.

Yep

https://en.m.wikipedia.org/wiki/Kinetic_bombardment

[Bored chemist]

Helium does not have a regiserable mass on 5he scales on earth, it floats up and out of the earth, yet its got mass.

Scales (usually) don't read mass- they read force.

You can measure mass in zero gravity.
https://en.wikipedia.org/wiki/Quartz_crystal_microbalance

[guest39538]

- A mass sitting stationary on scales is not accelerating, so the scales must oppose the acceleration by exerting an upwards force on the mass that equals the downwards force of gravity.

I stopped at the quoted part temporarily.

A mass at rest is still under the force of acceleration of g but simply not moving because the scales has solidity. It does not push back it simply has an opposing density.
The mass is caused because of the force.  No g equals no mass.
You and science are simply wrong on this information.   To push your scales into an hole , I assure you the scales will continue to accelerate.

m1=object
m2=scales

remember the scales are an object also, the spring in the scales compresses until it is dense enough to support the object equally.



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[guest39538]

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When an object opposes a force on another object, the Quantum voids of each object try to compress, however the ''walls''  of each Quantum void because they are likewise in polarities repulse this action.   When the ''walls'' gain more energy , they expand, but each 0 point remains the same value of energy, the ''walls'' pass right through space and space passes right through the walls, it is only the walls that gain greater r the space remaining united.

[Bored chemist]

It does not push back it simply has an opposing density.

Imagine a simple spring balance- just a spring, sat on a stable base like a table and with a pan on top of the spring.
You put a rock on the pan and it pushes down.
It moves the pan down a bit and the extent to which the pan moves depends on the weight of the rock.
The important fact to notice is that the spring is compressed a bit.
And that compressed spring really does push back on the rock- whether you like it or not.
So you are, as usual, wrong.

Why not learn some science rather than posting reams of nonsense?

[guest39538]

It does not push back it simply has an opposing density.

Imagine a simple spring balance- just a spring, sat on a stable base like a table and with a pan on top of the spring.
You put a rock on the pan and it pushes down.
It moves the pan down a bit and the extent to which the pan moves depends on the weight of the rock.
The important fact to notice is that the spring is compressed a bit.
And that compressed spring really does push back on the rock- whether you like it or not.
So you are, as usual, wrong.

Why not learn some science rather than posting reams of nonsense?

No, the rock, the pan and the spring is under the constant force of gravity and all the force is inwards.  When the spring compresses the spring increases in ''density'' and strength .  It ''pushes'' back but it does not push back.

When the pressure is removed from the spring the spring returns to original form where the ''pushing'' back remains although there is no longer any pressure.

It resists rather than pushing back.

P.s You told me my N-field was a load of crap basically, so therefore saying your own laws by Newton are also a load of crap.  So therefore if my N-field does not work then neither does your pushing back. So there....

added- Extending on the above I said previously but maybe in another way that the suns N-field pushes back the earths N-file and vice versus to give Q.F.S. 

[Bored chemist]

It ''pushes'' back but it does not push back.

I think we can stop there.
You have made it clear enough that you don't know what you are on about.

[alancalverd]

Here's what I learned by staying awake in primary school.

Consider a glass of water. Nothing is moving up or down. Now consider one cubic centimeter of that water, somewhere in the middle of the glass. It isn't moving. We know that 1 cc of water weighs 1 gram, because that's how we define a gram. If it isn't moving it must be because the surrounding water is pushing it up with 1 gram force, otherwise it would descend (because stuff falls if you don't push it upwards).

Now replace that 1 cc of water with 1 cc of air - a bubble, in the same position, but don't tell the surrounding water what we have done.  We know 1 cc of air weighs about 1 milligram, so the net upward force on the bubble must be 0.999 gram, so the bubble will rise.

That's how buoyancy  works.

[evan_au]

because the scales has solidity. It does not push back it simply has an opposing density. ...dense enough...When the spring compresses the spring increases in ''density''

What if you blow up a party balloon, and sit that on the scales.
Now balance your apples on the balloon.

The extremely low density of the air in the balloon successfully opposes the much greater density of the apples. The air in the balloon has a much lower density than the metal in the spring, the wood in the table, or the concrete in the floor.

So it really isn't reliant on density. It is primarily due to equal & opposite forces.

And, provided the deflection is small enough, air, metal, wood and concrete all act like springs, just with different ratios of force to compression (different spring constants).

To push your scales into an hole , I assure you the scales will continue to accelerate.

I agree - but your average supermarket does not have a bottomless pit extending to the other side of the Earth (or even to the center of the Earth).

The scales are mounted on a table, which deflects slightly under the weight of the scales + your bag of apples. The table exerts an upward force on the scales which is equal and opposite to the downward force of scales + apples.

The table sits on a concrete slab, which deflects very slightly under the weight of the table + scales + your bag of apples. The concrete exerts an upward force on the table which is equal and opposite to the downward force of table + scales + apples.

One of Newton's laws can be paraphrased as "every force has an equal and opposite force", which you can see mirrored in the case of apples, scales, table and concrete. It just so happens that we can measure the compression of the spring in the scales to determine the force exerted by the apples, and from this, to calculate the mass of the apples (assuming that they are sitting in a gravitational field of 9.8 m/s²).

If the scales fall down a hole, the apples no longer exert a force on the scales, and the scales no longer exert a force on the apples. The apples still have the same mass, but falling scales are useless for measuring it. 

[guest4091]

A mass at rest is still under the force of acceleration of g but simply not moving because the scales has solidity. It does not push back it simply has an opposing density.

You're almost correct.
Density is the ratio of mass to volume.
You need an opposing force.
That comes in the form of em resistance to compressing atoms in the spring example.
This correction should be acceptable.