Push gravity hijack from gravity, push or pull

[stupidnewton]

The push is not going to be anything.... because it is a pull - and attraction between masses. Seems pretty well covered above.

 

QUOTE: "Explanation requires a deal of intellect"

Yes - it requires intellect to explain it correctly... I suppose it requires intellect to come up with an idea that is totally wrong too - it shows you are thinking about it.

Can you explain the mechanics of a pull. Remember a car towing a trailer down the road is really pushing the trailer. Not pulling the trailer at all.

[swansont]

Can you explain the mechanics of a pull. Remember a car towing a trailer down the road is really pushing the trailer. Not pulling the trailer at all.

Explain that, please.

[stupidnewton]

Explain that, please.

The ball of the the car tow bar is pushing on the trailer coupling. The rear point of the car is behind the front point of the trailer.

 

The rear point of the car is pushing on the front point of the trailer.

 

In terms of language the car is 'pulling' the trailer as the trailer is essentially behind the car.

 

In terms of mechanics, though, the car is pushing the trailer. There is no 'pull' at all.

 

Mechanically the situation is no different to the entire trailer being in front of the car.

 

If you grab your desk and try and move it towards your self, you will probably language the situation as trying to 'pull' the desk towards your self. Mechanically though you will find your grab and exertion is a series of pushes. There will be some desk in front of your hand with respect of the direction you are trying to move the desk.

 

The point was everyone says gravity is a 'pull' but no-one can explain the mechanics of a 'pull'.

Edited December 1, 2016 by stupidnewton

[studiot]

 

stupidnewton post#24

Can you explain the mechanics of a pull.

 

It can indeed be difficult to allocate where pushes and pulls occur in a system of forces for instance in order to pull the desk in your example you will need to push with your feet against the floor.

 

However a body which can only contract can only exert a pull in its contraction.

This is the case in biomechanics in muscles for instance.

There are no muscles that can expand like a balloon to provide a push.

So pretty well all the muscles in your body work in pairs, each pulling in opposite directions, to generate the desired motion of the body part.

 

There is a very interesting book comparing the way nature achieves mechanical and other goals as compared to how artificial constructs achieve the same objectives.

 

Cats Paws and Catapaults

 

Steven Vogel

[swansont]

The ball of the the car tow bar is pushing on the trailer coupling. The rear point of the car is behind the front point of the trailer.

 

The rear point of the car is pushing on the front point of the trailer.

 

In terms of language the car is 'pulling' the trailer as the trailer is essentially behind the car.

 

In terms of mechanics, though, the car is pushing the trailer. There is no 'pull' at all.

 

Mechanically the situation is no different to the entire trailer being in front of the car.

 

If you grab your desk and try and move it towards your self, you will probably language the situation as trying to 'pull' the desk towards your self. Mechanically though you will find your grab and exertion is a series of pushes. There will be some desk in front of your hand with respect of the direction you are trying to move the desk.

Why does the rest of the trailer move?

 

The point was everyone says gravity is a 'pull' but no-one can explain the mechanics of a 'pull'.

 

The mechanics are not part of the Newtonian model, and you're conveniently ignoring that you have not explained the mechanics of a push.

[stupidnewton]

 

Why does the rest of the trailer move?

 

 

The mechanics are not part of the Newtonian model, and you're conveniently ignoring that you have not explained the mechanics of a push.

Not sure that I had been asked. A push is the exertion of matter upon matter.

 

The answer to your first question hasn't to do with whether or not the trailer is moving. It's to do with whether the rigid nature of the trailer is supplied by a system of pushes. I can't give you a categoric answer on that. But without anyone being able to explain the mechanics of a 'pull' you have to at least have an open mind on whether it all comes down to an exertion of matter upon matter at the most basic level.

 

Where I come from is a large mass M of say 12 kilo. A small mass m of 6 kilo. A total of 18 kilos. A mutual attraction factor of 72 according to Sir Isaac's law of mutual gravitation.

 

2 kilos are taken off the large mass. And put on the small mass. Now M is 10 kilo. And m is 8 kilo. According to Sir Isaac the same 18 kilos is now causing a mutual attraction factor of 80.

 

To put it another way, according to Sir Isaac, when man stands on the moon, the mutual attraction factor of the earth moon system has increased.

 

You don't have to be "Einstein" to see that Sir Isaac has made a mistake, the world have been believing a lie for three centuries etc.

Edited December 3, 2016 by stupidnewton

[AbstractDreamer]

But there is still [math] r^2 [/math] to consider.

 

[Math] F=G\frac{m_1m_2}{r^2} [/math]

 

So moving from mass from one object to another also changes the center of gravity for both objects.

 

But Newton's Theory of Gravity is only an approximation I think. Its good enough in non-relativistic situations.

Edited December 3, 2016 by AbstractDreamer

[studiot]

Not sure that I had been asked. A push is the exertion of matter upon matter.

 

The answer to your first question hasn't to do with whether or not the trailer is moving. It's to do with whether the rigid nature of the trailer is supplied by a system of pushes. I can't give you a categoric answer on that. But without anyone being able to explain the mechanics of a 'pull' you have to at least have an open mind on whether it all comes down to an exertion of matter upon matter at the most basic level.

 

Where I come from is a large mass M of say 12 kilo. A small mass m of 6 kilo. A total of 18 kilos. A mutual attraction factor of 72 according to Sir Isaac's law of mutual gravitation.

 

2 kilos are taken off the large mass. And put on the small mass. Now M is 10 kilo. And m is 8 kilo. According to Sir Isaac the same 18 kilos is now causing a mutual attraction factor of 80.

 

To put it another way, according to Sir Isaac, when man stands on the moon, the mutual attraction factor of the earth moon system has increased.

 

You don't have to be "Einstein" to see that Sir Isaac has made a mistake, the world have been believing a lie for three centuries etc.

 

So how does your calculations make Newton wrong?

 

You didn't say, merely claimed him to be wrong.

 

You have a good point, but

Rather than sneering at others, if you acted like a true scientist and investigated you might find out something new and even learn something.

 

All you have begun to show is that the gravitational attraction depends not only on the total mass but also on the distribution of that mass.

Exactly as Newton's equation.

 

Here is a plot of what happens as you vary the relative sizes of two masses held at constant distance apart with a constant total mass sum.

 

You get a non linear curve with a maximum force when the two masses are equal, and zero force when one of the masses is zero.

 

 

 

stupidnewton post#29

A push is the exertion of matter upon matter.

 

It is but that explanation is woefully inadequate.

 

Firstly a push can also be exerted by non matter agents.

Secondly just limiting the discussion to matter, are you aware of the difference between body forces, surface forces, direct and shear forces?

Edited December 3, 2016 by studiot

[swansont]

Not sure that I had been asked. A push is the exertion of matter upon matter.

You shouldn't have to be asked, considering the nature of your claim. "A push is the exertion of matter upon matter." isn't an explanation. I can just as easily say a pull is the exertion of matter upon matter.

 

The answer to your first question hasn't to do with whether or not the trailer is moving. It's to do with whether the rigid nature of the trailer is supplied by a system of pushes. I can't give you a categoric answer on that. But without anyone being able to explain the mechanics of a 'pull' you have to at least have an open mind on whether it all comes down to an exertion of matter upon matter at the most basic level.

So you've got nothing, basically.

 

Where I come from is a large mass M of say 12 kilo. A small mass m of 6 kilo. A total of 18 kilos. A mutual attraction factor of 72 according to Sir Isaac's law of mutual gravitation.

 

2 kilos are taken off the large mass. And put on the small mass. Now M is 10 kilo. And m is 8 kilo. According to Sir Isaac the same 18 kilos is now causing a mutual attraction factor of 80.

 

To put it another way, according to Sir Isaac, when man stands on the moon, the mutual attraction factor of the earth moon system has increased.

 

So?

 

You don't have to be "Einstein" to see that Sir Isaac has made a mistake, the world have been believing a lie for three centuries etc.

The proof of the pudding is in the eating. This so-called mistake allows us to accurately predict where satellites will go when launched, and what the orbits of celestial bodies are. It works. Helluva mistake.

[stupidnewton]

 

So how does your calculations make Newton wrong?

 

You didn't say, merely claimed him to be wrong.

 

You have a good point, but

Rather than sneering at others, if you acted like a true scientist and investigated you might find out something new and even learn something.

 

All you have begun to show is that the gravitational attraction depends not only on the total mass but also on the distribution of that mass.

Exactly as Newton's equation.

 

Here is a plot of what happens as you vary the relative sizes of two masses held at constant distance apart with a constant total mass sum.

 

You get a non linear curve with a maximum force when the two masses are equal, and zero force when one of the masses is zero.

 

grav1.jpg

 

 

It is but that explanation is woefully inadequate.

 

Firstly a push can also be exerted by non matter agents.

Secondly just limiting the discussion to matter, are you aware of the difference between body forces, surface forces, direct and shear forces?

 

 

Your graph has failed to support Sir Isaac's law of gravity. Requires m to be non existent to be plotted. The law is specifically about mutual attraction of two masses. Graph requires the elimination of one of the masses of a two mass system to have its Y axis beginning point. Your normal force would be tending to infinity as m tended zero if your graph was based on realism.

You shouldn't have to be asked, considering the nature of your claim. "A push is the exertion of matter upon matter." isn't an explanation. I can just as easily say a pull is the exertion of matter upon matter.

 

So you've got nothing, basically.

 

 

So?

 

The proof of the pudding is in the eating. This so-called mistake allows us to accurately predict where satellites will go when launched, and what the orbits of celestial bodies are. It works. Helluva mistake.

So you just as easily say a push is a pull. Interesting.

 

Accurate predictions are never proof of theory, let alone absolute proof. That notion is a false science in its self. Not much different to predicting the sun goes around the earth because we see it half the time. Sputnik 1 didn't go into its predicted orbit did it. Prediction is over rated as the owner of human beings knowing truth.

[studiot]

 

stupidnewton post#33

Your graph has failed to support Sir Isaac's law of gravity. Requires m to be non existent to be plotted. The law is specifically about mutual attraction of two masses. Graph requires the elimination of one of the masses of a two mass system to have its Y axis beginning point. Your normal force would be tending to infinity as m tended zero if your graph was based on rea

 

 

Either you are trolling or you really don't understand even high school mathematics.

 

My graph is sound and quite understandable using only high school mathematics.

[swansont]

Accurate predictions are never proof of theory, let alone absolute proof. That notion is a false science in its self.

Nobody has claimed otherwise.

[stupidnewton]

 

 

Either you are trolling or you really don't understand even high school mathematics.

 

My graph is sound and quite understandable using only high school mathematics.

You haven't addressed the issue. 19 kilo x 1 kilo does not equal 18 kilo x 2 kilo etc.

 

As was stated originally, when man stood on the moon, according to Newton, the mutual attraction of the earth and moon increased. The earth was of less mass. The moon was of more mass. Meaning the product of the masses of the bodies had increased when a moonshot reached the moon.

 

If you accept Sir Isaac's law, you need to be able to explain how a moon shot increases the mutual attraction between the two bodies, etc. You haven't as yet, nor has anyone else. The law is obviously open to question until someone can so explain. After all, this is just a simple intriguing question of science.

Edited December 5, 2016 by stupidnewton

[Mordred]

If you learned basic physics such as those posted by Studiot you can easily figure out the effect you just described.

 

As Swansont already stated "So" meaning so what.

Edited December 5, 2016 by Mordred

[studiot]

You haven't addressed the issue. 19 kilo x 1 kilo does not equal 18 kilo x 2 kilo etc.

 

As was stated originally, when man stood on the moon, according to Newton, the mutual attraction of the earth and moon increased. The earth was of less mass. The moon was of more mass. Meaning the product of the masses of the bodies had increased when a moonshot reached the moon.

 

If you accept Sir Isaac's law, you need to be able to explain how a moon shot increases the mutual attraction between the two bodies, etc. You haven't as yet, nor has anyone else. The law is obviously open to question until someone can so explain. After all, this is just a simple intriguing question of science.

 

If you look over this thread, you will note that your issue (underlined) is off the topic of this thread.

 

I guess that the moderators have allowed you (and me) to continue, as with a previous poster's off topic stuff, because the original question was well discussed some months ago.

 

My responses to your issue have each time acknowledged where you were right or had a good point to make. Including this one.

 

 

 

 

If you accept Sir Isaac's law, you need to be able to explain how a moon shot increases the mutual attraction between the two bodies, etc. You haven't as yet, nor has anyone else. The law is obviously open to question until someone can so explain. After all, this is just a simple intriguing question of science.

 

You clearly haven't read posts given by myself and others properly or you would has seen the answer to this question.

Furthermore Newtonian gravity is not the only mechanical property to be affected by the distribution of mass as well as the absolute value.

Knowing this is key to understanding the difference between moment of inertia and product of inertia for instance.

 

Unfortunately your intransigent rudeness in replying is getting in the way of your own understanding and proper expansion of the explanation, perhaps even leading to such ridiculous claims as

 

'something multiplied by zero tends to infinity'

 

 

Your graph has failed to support Sir Isaac's law of gravity. Requires m to be non existent to be plotted. The law is specifically about mutual attraction of two masses. Graph requires the elimination of one of the masses of a two mass system to have its Y axis beginning point. Your normal force would be tending to infinity as m tended zero if your graph was based on realism.

 

Edited December 5, 2016 by studiot

[stupidnewton]

If you learned basic physics such as those posted by Studiot you can easily figure out the effect you just described.

 

As Swansont already stated "So" meaning so what.

This is getting silly. What basic physics have has not been learnt. Newton's laws of motion, his law of mutual gravitation, kinetic energy, pressure, weight, kinematics, what?

 

The moon's mass has increased and the earth's mass decreased. This is real. There are flags from earth on the moon right now. According to Sir Isaac's law of mutual gravitation, the mutual attraction of the two bodies is greater with flags having switched from the earth to the moon. The larger body has less mass. The smaller body has that mass. The product of the masses of the two bodies is now greater.

 

Saying someone is uneducated because they ask the question doesn't real answer the question. It is a very genuine issue for anyone with intellectual integrity. The graph simply did not explain how 19 x 1 = 18 x 2.

[DrKrettin]

The moon's mass has increased and the earth's mass decreased. This is real. There are flags from earth on the moon right now. According to Sir Isaac's law of mutual gravitation, the mutual attraction of the two bodies is greater with flags having switched from the earth to the moon. The larger body has less mass. The smaller body has that mass. The product of the masses of the two bodies is now greater.

 

 

 

 

That observation in itself does not give you the right to conclude that Newton's Law is wrong - that is an extremely simplistic argument. What you need to consider is the work needed to transport the flag from the Earth to the Moon, and the change in potential energy of the flag in moving it.

 

I might even be tempted to work out the maths here. But given that the object would be to demonstrate the validity of a law which would have been rejected ages ago if your argument actually had some merit, I'll just leave it to you to collect your Nobel prize.

[swansont]

This is getting silly. What basic physics have has not been learnt. Newton's laws of motion, his law of mutual gravitation, kinetic energy, pressure, weight, kinematics, what?

 

The moon's mass has increased and the earth's mass decreased. This is real. There are flags from earth on the moon right now. According to Sir Isaac's law of mutual gravitation, the mutual attraction of the two bodies is greater with flags having switched from the earth to the moon. The larger body has less mass. The smaller body has that mass. The product of the masses of the two bodies is now greater.

 

Saying someone is uneducated because they ask the question doesn't real answer the question. It is a very genuine issue for anyone with intellectual integrity. The graph simply did not explain how 19 x 1 = 18 x 2.

 

 

19 x 1 ≠ 18 x 2. Nobody is claiming that it is.

 

So what? You are insisting that for a constant mass and distance, the force should be constant, as if there is some secret conservation law in existence.

 

Why (i.e. on what physics basis) should the force be constant?

[Mordred]

This is getting silly. What basic physics have has not been learnt. Newton's laws of motion, his law of mutual gravitation, kinetic energy, pressure, weight, kinematics, what?

 

The moon's mass has increased and the earth's mass decreased. This is real. There are flags from earth on the moon right now. According to Sir Isaac's law of mutual gravitation, the mutual attraction of the two bodies is greater with flags having switched from the earth to the moon. The larger body has less mass. The smaller body has that mass. The product of the masses of the two bodies is now greater.

 

Saying someone is uneducated because they ask the question doesn't real answer the question. It is a very genuine issue for anyone with intellectual integrity. The graph simply did not explain how 19 x 1 = 18 x 2.

Yes but that has nothing to do with Pull instead of push now does it. What you described is simply moving mass from one location and placing it at another. This will obviously cause a change in mutual attraction.

 

As Studiot mentioned the distribution effects is also easily shown under Newtons laws

Edited December 5, 2016 by Mordred

[stupidnewton]

 

 

19 x 1 ≠ 18 x 2. Nobody is claiming that it is.

 

So what? You are insisting that for a constant mass and distance, the force should be constant, as if there is some secret conservation law in existence.

 

Why (i.e. on what physics basis) should the force be constant?

Not secret.

 

What I am saying is just obvious and needs an answer. . How did Neil Armstrong increase the mutual attraction between the earth and the moon when he was there? If you can explain, please do. If you want to continue the obfuscation, doesn't bother me. But doesn't answer this sincere question either.

 

[studiot]

Not secret.

 

What I am saying is just obvious and needs an answer. . How did Neil Armstrong increase the mutual attraction between the earth and the moon when he was there? If you can explain, please do. If you want to continue the obfuscation, doesn't bother me. But doesn't answer this sincere question either.

 

 

 

I asked you two polite questions in my post#31, correctly identified by the question marks at their ends.

.

You have subsequently refused/failed to offer any answer on either of them

 

Why do you expect others to answer any of your questions under such circumstances?

Edited December 6, 2016 by studiot

[swansont]

Not secret.

 

What I am saying is just obvious and needs an answer. . How did Neil Armstrong increase the mutual attraction between the earth and the moon when he was there? If you can explain, please do. If you want to continue the obfuscation, doesn't bother me. But doesn't answer this sincere question either.

 

 

 

Because the force of attraction is proportional to the product of the masses. That's why. That's how gravity behaves. If the sum of the masses is constant, at a given r, the force will be maximum when the individual masses are equal. It's a trivial math exercise to show that, if you know basic calculus.

 

 

You are claiming that gravity should behave some other way, but you have given no justification for that. It's not obvious, it's wrong.

[stupidnewton]

 

 

I asked you two polite questions in my post#31, correctly identified by the question marks at their ends.

.

You have subsequently refused/failed to offer any answer on either of them

 

Why do you expect others to answer any of your questions under such circumstances?

Can only see one question there, is polite, no worries.

 

http://www.physicsclassroom.com/class/circles/Lesson-3/Newton-s-Law-of-Universal-Gravitation

 

Seems to say if one mass is doubled the force of mutual attraction is doubled. Meaning the mass present determines the force of attraction.

 

If the mass present is distributed in another way, the mass present is throwing a different force of attraction..

 

See the contradiction?

 

 

Because the force of attraction is proportional to the product of the masses. That's why. That's how gravity behaves. If the sum of the masses is constant, at a given r, the force will be maximum when the individual masses are equal. It's a trivial math exercise to show that, if you know basic calculus.

 

 

You are claiming that gravity should behave some other way, but you have given no justification for that. It's not obvious, it's wrong.

Sir Isaac's law of mutual attraction says nothing about a maximum force when the masses are equal. The law says for any two masses. Your argument is a mass of 9 and 1 have lesser attraction than masses of 8 and 2. Why?

[DrKrettin]

 

Sir Isaac's law of mutual attraction says nothing about a maximum force when the masses are equal. The law says for any two masses. Your argument is a mass of 9 and 1 have lesser attraction than masses of 8 and 2. Why?

 

Simple calculus. Let's say the force F = GMm/r^2 where the two bodies are at distance r and have masses M and m.

 

If the distance is constant we can write F = kMm where k is a constant. Now we say that the sum of the two masses is also constant, so M + m = c, another constant

 

So m = c - M

 

F = kM(c - M) = kcM - kM^2

 

dF/dM = kc - 2kM = 0 when c = 2M, i.e. M = m, and the second differential is negative, so that is a maximum

 

That shows that under those conditions, the force is a maximum when the two bodies are of equal mass. It follows that 9 and 1 have less attraction than 8 and 2.

[swansont]

 

Sir Isaac's law of mutual attraction says nothing about a maximum force when the masses are equal. The law says for any two masses. Your argument is a mass of 9 and 1 have lesser attraction than masses of 8 and 2. Why?

 

 

Because that's how math works.

 

There's no contradiction because there is no legitimate reason to think the attraction would be constant if you re-distribute the masses.