Deductively proving the conservation of momentum

In summary, the conversation revolves around the possibility of deductively proving the conservation of momentum without the use of observation or experience. One approach is through Noether's theorem, which assumes the invariance of physical laws under translations in space. Another approach, involving Pauli's exclusion principle, is purely quantum mechanical and not related to Newton's third law. However, the concept of a force is purely classical. The conversation also touches on the idea of proving conservation of momentum through pure logic, without recourse to experiment, but this is not possible. Ultimately, the question is raised about the relevance of considering non-scientific questions in a scientific forum.
  • #1
Mektrik
3
0
I won't go into all the details but, to summarize, I'm planning on writing something on the philosophy of science and I was wondering if it's possible to deductively prove, that is without the use of observation or experience, the conservation of momentum. I know that it's possible to prove it using Newton's third law, but that itself requires induction.

As a side note, without meaning to sound too pretentious, is it possible to prove Newton's third law using Pauli's exclusion principle? If so, is the exclusion principle deductive?

Anyway, apologies for my naivety and I look forward to seeing your responses.
 
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  • #2
Yes, it's called Noether's theorem. If you make the assumption that the laws of physics are invariant under translations in space - that is the laws of physics are the same here as they are in China or on the moon or in another galaxy, then the quantity we define as [itex] m\vec{v} [/itex] in classical mechanics is conserved.

Pauli exclusion principle is purely quantum mechanical, and has nothing to do with Newton's third law. The whole concept of a force is a purely classical idea.
 
  • #3
dipole said:
Yes, it's called Noether's theorem. If you make the assumption that the laws of physics are invariant under translations in space - that is the laws of physics are the same here as they are in China or on the moon or in another galaxy, then the quantity we define as [itex] m\vec{v} [/itex] in classical mechanics is conserved.

Pauli exclusion principle is purely quantum mechanical, and has nothing to do with Newton's third law. The whole concept of a force is a purely classical idea.

Ahh, for reasons which I won't go into, is there a way to do it without using Noether's theorem? Sorry for not mentioning this earlier and thanks for the reply!
 
  • #4
Is there a way to prove conservation of momentum based on the pure force of logic along the lines of "cogito ergo sum" without recourse to experiment? Nope, certainly not.

One can conceive of a universe in which reactionless drives exist. Science fiction is full of such creations.
 
  • #5
jbriggs444 said:
Is there a way to prove conservation of momentum based on the pure force of logic along the lines of "cogito ergo sum" without recourse to experiment? Nope, certainly not.

One can conceive of a universe in which reactionless drives exist. Science fiction is full of such creations.

One could 'conceive' the Moon being made of green cheese but is it relevant to Science?
 
  • #6
sophiecentaur said:
One could 'conceive' the Moon being made of green cheese but is it relevant to Science?

Certainly not. But the question that was posed was not about science. It specifically repudiated the use of observation and experience.
 
  • #7
jbriggs444 said:
Certainly not. But the question that was posed was not about science. It specifically repudiated the use of observation and experience.

I have to ask what the point is of considering deliberately non-Science questions* in a Science Forum.
*questions / hypotheses that are not testable.
 

1. How is the conservation of momentum proven deductively?

The conservation of momentum is proven deductively through the application of Newton's laws of motion and the principle of conservation of energy. These laws state that the total momentum of a closed system remains constant unless acted upon by an external force.

2. What is a closed system in relation to the conservation of momentum?

A closed system is a physical system that does not exchange any matter or energy with its surroundings. In the context of the conservation of momentum, a closed system is necessary in order to accurately measure and observe the total momentum of the system before and after a collision or interaction.

3. Why is the conservation of momentum important?

The conservation of momentum is important because it is a fundamental principle of physics that is applicable to a wide range of systems, from subatomic particles to large-scale celestial bodies. It helps to explain and predict the behavior of objects in motion and is essential in many areas of science and engineering.

4. Can the conservation of momentum be violated?

No, the conservation of momentum cannot be violated. This principle is a fundamental law of physics and has been extensively tested and confirmed through experiments and observations. If a change in momentum is observed in a closed system, it can always be attributed to an external force acting on the system.

5. How does the conservation of momentum relate to real-world scenarios?

The conservation of momentum has numerous applications in real-world scenarios, such as in collisions between objects, rocket propulsion, and even sports. For example, in a game of pool, the total momentum of the cue ball and the other balls on the table remains constant before and after each shot, demonstrating the principle of conservation of momentum in action.

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