VARIPEND

[Bufofrog]

1 hour ago, butovsv said:

I beg your pardon if I did not answer any question.
Ready to answer any question!
There are no secrets!

Oh good.  One of the questions you didn't answer was from Swansont, he asked what is the m(liquid) in your equation since your diagram doesn't seem to have a liquid component.

Edited August 22, 2019 by Bufofrog

[butovsv]

10 minutes ago, Bufofrog said:

Oh good.  On of the questions you didn't answer was from Swansont, he asked what is the m(liquid) in your equation since your diagram doesn't seem to have a liquid component. 

 

Edited August 22, 2019 by butovsv

[Bufofrog]

Is the above seriously supposed to be an answer to my question?

[butovsv]

Just now, Bufofrog said:

Is the above seriously supposed to be an answer to my question? 

Is that not enough?

On 8/20/2019 at 10:27 AM, butovsv said:

A VARIPEND is any centrifugal pump operating in the mode of periodically breaking the flow of a pumped substance.

                              

 

 

 

 

[swansont]

1 hour ago, butovsv said:

"Resulting force" is the change in the total momentum of a mechanical system.

 

Still wrong.

 

1 hour ago, butovsv said:

Write the dependence of the "center of mass of the system of bodies" on the "resulting force".

F=ma

 

1 hour ago, butovsv said:

 I hope that after Dr Swanson remembers the basic concepts of Mechanics, his "atomic clock" will work even better!

They're already the best cold-atom clocks in the world, but whatever...

 

1 hour ago, butovsv said:

"Dr Swanson" wrote:

Such a phrase is permissible for a student.

Your attempts would not be permissible for a student who wished to pass their course.

 

1 hour ago, butovsv said:

But VERY embarrassing for an "atomic clock specialist"!

I note the complete lack of physics in your attempted rebuttal. I, and others, have pointed out errors, and you have ignored the corrections, and repeated the mistakes.

Force and momentum, for example, are not the same thing. If they were, we would not need two names for them. They would be interchangeable in equations, but they are not. They would have the same units, but they do not.

 

 

1 hour ago, Mordred said:

Incorrect force is not momentum. You should really learn the definitions of each term. For example the unit of force is a Newton. Which is the amount of energy required to move a 1 kg mass one metre in one second.

I think you forgot to proof-read this. Force isn't energy.  (or were checking to see if anyone caught the error?)

A Newton is the force necessary to accelerate 1 kg at 1m/s^2

1 hour ago, butovsv said:

 
Ready to answer any question!

For real? You will answer the questions?

1 hour ago, butovsv said:

I will show how the Mass Center of the Varipend system is calculated:

 

rc(t)=mliquid(t)r1(t)+mcase(t)r2(t)M

 

 

What does the blue arc physically represent? How does it get smaller? What force causes it to move?

What is liquid in your "mechanical" "pendulum"?

Why is the CoM of what looks to be a circularly symmetric body (body #2) not located at the origin?

 

1 hour ago, butovsv said:

In order to calculate the coordinates of the CM system at any time, it is necessary to know the masses and coordinates of the parts of the system.
And the masses and coordinates of the parts of the system change over time.

What component mass changes over time?

 

[butovsv]

11 minutes ago, swansont said:

2 hours ago, butovsv said:

"Resulting force" is the change in the total momentum of a mechanical system.

 

Still wrong.

hM-m.....

It's good that you are literate - you all know!
You know where the truth is, and where the lie!

Watch attentively!

 

 

Law of Conservation of Momentum

The law of conservation of momentum  states that the vector sum of the momenta of all the bodies of the system is constant if the vector sum of the external forces acting on the system of bodies is zero.

In the language of mathematics, this law is written like this:

[math]\vec P(t) = \sum {{m_i}(t){{\dot r}_i}(t)}  = const[/math]

[math]\frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}}  = 0[/math]

 

If: [math]\frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}}  \ne 0[/math]  - this means that the system is "affected by external forces."

Do you know what these "external forces" are, dear "atomic clock specialist?"

They are equal to this:

[math]{{\vec F}^e} = \frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}} [/math]

 

 

This is Physics.
The science is ....

 

 

 

Edited August 22, 2019 by butovsv

[swansont]

21 minutes ago, butovsv said:

Is that not enough?

Type out the f**ing answer. Try it without using any animations, or simply regurgitating a previous response. EXPLAIN it.

2 minutes ago, butovsv said:

hM-m.....

It's good that you are literate - you all know!
You know where the truth is, and where the lie!

Watch attentively!

 

 

Law of Conservation of Momentum

The law of conservation of momentum  states that the vector sum of the momenta of all the bodies of the system is constant if the vector sum of the external forces acting on the system of bodies is zero.

In the language of mathematics, this law is written like this:

[math]\vec P(t) = \sum {{m_i}(t){{\dot r}_i}(t)}  = const[/math]

[math]\frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}}  = 0[/math]

 

If

 

[math]\frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}}  \ne 0[/math]  - this means that the system is "affected by external forces."

Do you know what these "external forces" are, dear "atomic clock specialist?"

They are equal to this:

[math]{{\vec F}^e} = \frac{{d\vec P(t)}}{{dt}} = \frac{{d(\sum {{m_i}(t){{\dot r}_i}(t)} )}}{{dt}} = \sum {{m_i}{{\ddot r}_i}}  + \sum {{{\dot m}_i}{{\dot r}_i}} [/math]

 

 

This is Physics.
The science is ....

 

And yet, momentum is not force, and force is not momentum.

[butovsv]

11 minutes ago, swansont said:

Quote

Write the dependence of the "center of mass of the system of bodies" on the "resulting force".

F=ma

And what is the mass of the "Center of the Mass of the system of bodies" equal to?

 

[Strange]

1 minute ago, butovsv said:

And what is the mass of the "Center of the Mass of the system of bodies" equal to?

!

Moderator Note

You need to stop asking questions and explain your idea.

 

[swansont]

1 minute ago, butovsv said:

And what is the mass of the "Center of the Mass of the system of bodies" equal to?

 

Whatever the total mass is. This is your example. I don't know the value.

 

Stop stalling and answer the questions that have been asked of you.

[butovsv]

13 minutes ago, swansont said:

Quote

"Dr Swanson" wrote:

Such a phrase is permissible for a student.

Your attempts would not be permissible for a student who wished to pass their course.

Then correct your phrase!
Just take it and write the Tsetra Mass equation of the system of bodies!
And look at what this value depends on!

In order not to disgrace ....

[swansont]

Just now, butovsv said:

Then correct your phrase!
Just take it and write the Tsetra Mass equation of the system of bodies!
And look at what this value depends on!

In order not to disgrace ....

Stop stalling and answer the questions that have been asked of you.

[butovsv]

3 minutes ago, swansont said:

Whatever the total mass is. This is your example. I don't know the value.

 

Stop stalling and answer the questions that have been asked of you. 

I apologize!
I have said this many times already!

The center of Mass is not a material object!
The CM does not have mass!
Newton’s second law cannot be applied to the Center of Mass!

The Mass Center is calculated as follows:

[math]{{\vec R}_c}(t) = \frac{{\sum {{m_i}(t){r_i}(t)} }}{{\sum {{m_i}} (t)}}[/math]

 

But like this:

[math]{{\vec R}_c}(t) = {{\vec R}_c}(0) + {{\vec V}_c}(t)t + \frac{1}{2}\frac{{{{\vec F}^e}}}{M}{t^2}[/math]

coordinates of a single material body with mass are calculated.

 

 

 

5 minutes ago, swansont said:

7 minutes ago, butovsv said:

And what is the mass of the "Center of the Mass of the system of bodies" equal to?

 

Whatever the total mass is. This is your example. I don't know the value.

 

Stop stalling and answer the questions that have been asked of you. 

 

Here are the coordinates of the Mass Center of a certain system:

[math]\vec R = \frac{{\sum {{m_i}{{\vec r}_i}} }}{{\sum {{m_i}} }} = \frac{{{m_1}{{\vec r}_1} + {m_2}{{\vec r}_2} + {m_3}{{\vec r}_3} + ... + {m_i}{{\vec r}_i}}}{{{m_1} + {m_2} + {m_3} + ... + {m_i}}}[/math]

Please help me find the "total mass."

 

 

 

That "total mass", which cannot move in any way without the "acceleration" caused by "external force"!

 

 

The unit of measurement of the Center of Mass of the system of bodies is the unit of length of the selected Reference System. Meters, feet, inches, elbows, yards, miles .....

I would be very grateful to you, “atomic clock specialist,” if you would explain to me, deeply illiterate, how to apply Sir Newton’s second law to “miles”.

Thank you in advance!

[Bufofrog]

It seems clear to me that you are unable to answer the questions put to you.  You simply have an animation that shows a physically impossible situation and then hand wave and dodge questions about the animation since it is indefensible.

This thread is due to be tossed in to the trash can soon.  It certainly has my vote for the trash!

[butovsv]

35 minutes ago, swansont said:

Quote

Write the dependence of the "center of mass of the system of bodies" on the "resulting force".

F=ma

It is very, very, very, very WRONG.
Have I explained in sufficient detail?

 

1 minute ago, Bufofrog said:

It seems clear to me that you are unable to answer the questions put to you.  You simply have an animation that shows a physically impossible situation and then hand wave and dodge questions about the animation since it is indefensible.

This thread is due to be tossed in to the trash can soon.  It certainly has my vote for the trash! 

What is the failure of my answer?

 

2 minutes ago, Bufofrog said:

You simply have an animation that shows a physically impossible situation

 

The total momentum of this system is zero.

There is no other solution to the balance of the total momentum of this system!


But if you see with your own eyes the center of mass of this system, you see how the CM moves, violating the laws of conservation, then this is exclusively your personal problem!

 

 

 

 

 

This beautiful task should not be sent to the "trash can".
You need to throw your naive childish sensations of "banal physics" into the basket!

The knowledge "twice two is always four" is very good knowledge!
Right!

But it will not help in extrapolating the function of the CM of the system of bodies in which the parts change masses!

[Bufofrog]

14 minutes ago, butovsv said:

What is the failure of my answer?

You did not answer what m(liquid) is in your animation.

And a guess what, your next reply won't answer it either.  I don't know why you won't answer, I only you won't.

Very odd...

[koti]

16 minutes ago, butovsv said:

It is very, very, very, very WRONG.
Have I explained in sufficient detail?

 

You are stalling, manipulating and being a complete d1*k. I’m here to learn physics and your way of explaining things is not helping. Change your attitude or gtfo mr. Laser. 

[Bufofrog]

21 minutes ago, butovsv said:

But if you see with your own eyes the center of mass of this system, you see how the CM moves, violating the laws of conservation, then this is exclusively your personal problem!

I can make an animation of a person flying by flapping his arms, the animation does not mean it is possible in reality!

Edited August 22, 2019 by Bufofrog

[butovsv]

 

The center of the mass system of bodies is a function of 2 (two) time-dependent variables.

[math]{{\vec R}_c}(t) = \frac{{\sum {{m_i}(t){r_i}(t)} }}{{\sum {{m_i}} (t)}}[/math]

 

The velocity of the Center of Mass is a derivative of the radius vector:

[math]{v_c}(t) = \frac{{d{R_c}(t)}}{{dt}} = \frac{{\sum {{m_i}{{\dot r}_i}(t)} }}{{\sum {{m_i}} }} + \frac{{\sum {{{\dot m}_i}{r_i}(t)} }}{{\sum {{m_i}} }}[/math]

 

If you want to know the antiderivative of a function, try to integrate the derivative of this function:

[math]{R_c}(t) = \int {{v_c}(t)} dt = \int {\left( {\frac{{\sum {{m_i}{{\dot r}_i}(t)} }}{{\sum {{m_i}} }} + \frac{{\sum {{{\dot m}_i}{r_i}(t)} }}{{\sum {{m_i}} }}} \right)} dt = \int {\left( {\frac{{\sum {{m_i}{{\dot r}_i}(t)} }}{{\sum {{m_i}} }}} \right)} dt + \int {\left( {\frac{{\sum {{{\dot m}_i}{r_i}(t)} }}{{\sum {{m_i}} }}} \right)} dt[/math]

 

The radius vector of the CM of the system of bodies is the result of the addition of two "vectors" - the radius vector of inertial displacement and the pseudovector of deformation of the system of bodies.

 

 

 

[Bufofrog]

3 minutes ago, butovsv said:

 

The center of the mass system of bodies is a function of 2 (two) time-dependent variables.

R⃗ c(t)=∑mi(t)ri(t)∑mi(t)

 

The velocity of the Center of Mass is a derivative of the radius vector:

vc(t)=dRc(t)dt=∑mir˙i(t)∑mi+∑m˙iri(t)∑mi

 

If you want to know the antiderivative of a function, try to integrate the derivative of this function:

Rc(t)=∫vc(t)dt=∫(∑mir˙i(t)∑mi+∑m˙iri(t)∑mi)dt=∫(∑mir˙i(t)∑mi)dt+∫(∑m˙iri(t)∑mi)dt

 

The radius vector of the CM of the system of bodies is the result of the addition of two "vectors" - the radius vector of inertial displacement and the pseudovector of deformation of the system of bodies.

 

 

 

Still dodging and obfuscating.  Why change tactics, right?

[butovsv]

2 minutes ago, Bufofrog said:

I can make an animation of a person flying by flapping his arms, the animation does not .mean it is possible in reality! 

The immutability of a human impulse is the immutability of a zero human momentum.

And the immobility of the Varipend systems looks like this:

The total momentum of this system is zero.

 

You can try to depict this system with a constant CM and a constant total momentum.
You won’t succeed.

 

 

[swansont]

21 minutes ago, butovsv said:

It is very, very, very, very WRONG.
Have I explained in sufficient detail?

You have not explained at all why you think Newton's second law* is wrong.

*as applied to a system of constant mass, as implied by having a center of mass

 

21 minutes ago, butovsv said:

 

What is the failure of my answer?

 

You gave an answer?

21 minutes ago, butovsv said:

 

 

The total momentum of this system is zero.

 

 

You keep saying this, but refuse to explain what, specifically, is going on in the animation.

What are the black balls? What is happening to them? Why do they change direction?

 

 

21 minutes ago, butovsv said:

There is no other solution to the balance of the total momentum of this system!
 

Here's my solution: Drawings/animations do not have to follow the laws of physics.

 

21 minutes ago, butovsv said:

But if you see with your own eyes the center of mass of this system, you see how the CM moves, violating the laws of conservation, then this is exclusively your personal problem!

No, I'm pretty sure the burden of explanation is on you, and simply repeating yourself without doing so will end this thread.

 

Are you refusing to answer the other questions that have been asked of you?

10 minutes ago, Bufofrog said:

You did not answer what m(liquid) is in your animation.

And a guess what, your next reply won't answer it either.  I don't know why you won't answer, I only you won't.

Very odd...

I'm guessing the equation was copy-pasted from somewhere else. Which also explains why he is only posting general equations and not actually applying them to the problems that have been posted. No independent physics knowledge being displayed.

[Mordred]

1 hour ago, swansont said:

 

I think you forgot to proof-read this. Force isn't energy.  (or were checking to see if anyone caught the error?)

A Newton is the force necessary to accelerate 1 kg at 1m/s^2

Thanks for the catch it was 5 am when I typed that and hadn't had my first coffee lol

[Strange]

1 hour ago, butovsv said:

The immutability of a human impulse is the immutability of a zero human momentum.

And the immobility of the Varipend systems looks like this:

The total momentum of this system is zero.

You can try to depict this system with a constant CM and a constant total momentum.
You won’t succeed.

!

Moderator Note

OK. That's enough. If you are not able to explain you idea or answer questions, this thread is closed. Do not bring this up again.