Theoretical work on how momentum is carried or encoded?

In summary, the conversation discusses the concept of momentum and how particles continue to move in a particular direction. The question of why this happens and what mediates it is brought up, along with the relevance of Newton's 3 laws of motion and Noether theorem in understanding conservation laws. The conversation concludes with the understanding that there is no definitive answer to the "why's" in physics, and that it is important to stick to classical mechanics before delving into more complex theories.
  • #1
Benwade
11
0
I am not looking for homework help on how to do the math for vectors and momentum. Nor do I expect to understand the answer theoretically, but is/has any work been done that examines what it is that "carries" or encodes or transfers momentum? By this I mean that a particle receives energy from another particle and it moves in a particular direction. How does that particle "know" to continue in a particular direction. I know it's momentum and that the particle has to move, but why always in the same direction? Of course the flip side of that question is "why not?" for which I have no answer.
 
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  • #2
Benwade said:
How does that particle "know" to continue in a particular direction

it doesn't "know" anything

Benwade said:
I know it's momentum and that the particle has to move, but why always in the same direction?

Are you familiar with Newton's 3 laws of motion ?
particularly #1Dave
 
  • #3
Benwade said:
I am not looking for homework help on how to do the math for vectors and momentum. Nor do I expect to understand the answer theoretically, but is/has any work been done that examines what it is that "carries" or encodes or transfers momentum? By this I mean that a particle receives energy from another particle and it moves in a particular direction. How does that particle "know" to continue in a particular direction. I know it's momentum and that the particle has to move, but why always in the same direction? Of course the flip side of that question is "why not?" for which I have no answer.

Unfortunately, your question is actually a lot more "fundamental" and deeper than you think. What you are really asking is "why is there conservation of linear momentum?", and via Noether theorem, you are also directly asking "why does the classical empty space have translational symmetry?" (every conservation laws has an underlying symmetry principle).

We have no answers to those right now, the same way we have no answers to the many other "why's" in physics. Some think that physics doesn't address the why's, because the more you dig deeper into those reasons, you came up at the end with a description. But that is delving purely into philosophy.

Zz.
 
  • #4
davenn said:
it doesn't "know" anything
Are you familiar with Newton's 3 laws of motion ?
particularly #1Dave
Hi Dave, Thank you for your reply. I'm going to make a wild guess and say that you're referring to his 1st rule:
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
Yeah, I've heard of it. The question remains - why? How is that mediated. What makes it not "decide" well, I've got energy, I have to go somewhere. According to quantum mechanics I could be anywhere, why can't I go in another direction for while?
 
  • #5
Benwade said:
Hi Dave, Thank you for your reply. I'm going to make a wild guess and say that you're referring to his 1st rule:
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
Yeah, I've heard of it. The question remains - why? How is that mediated. What makes it not "decide" well, I've got energy, I have to go somewhere. According to quantum mechanics I could be anywhere, why can't I go in another direction for while?

First of all, you need to learn how to walk first before attempting to run. Invoking quantum mechanics into this will not help, and as can be seen already, you are confusing yourself unnecessarily (besides, your understanding of QM is flawed here). So stick to classical mechanics for now.

Secondly, you'll notice that the object could actually be stationary in some reference frame, and that YOU are the one moving. So why should that object, just by coincidence, be at rest in your frame of reference? What makes you so special?

So there is nothing to "mediate" that. When there are no external forces involved, it is actually extremely unusual for an object to be stationary with respect to you. Think about it.

And as I expected, my reply to you on the nature of conservation laws and symmetry may have gone over your head. It is actually quite relevant here with your last question.

Zz.
 
  • #6
ZapperZ said:
First of all, you need to learn how to walk first before attempting to run. Invoking quantum mechanics into this will not help, and as can be seen already, you are confusing yourself unnecessarily (besides, your understanding of QM is flawed here). So stick to classical mechanics for now.

Secondly, you'll notice that the object could actually be stationary in some reference frame, and that YOU are the one moving. So why should that object, just by coincidence, be at rest in your frame of reference? What makes you so special?

So there is nothing to "mediate" that. When there are no external forces involved, it is actually extremely unusual for an object to be stationary with respect to you. Think about it.

And as I expected, my reply to you on the nature of conservation laws and symmetry may have gone over your head. It is actually quite relevant here with your last question.

Zz.
You're absolutely right. about the nature of conservation laws, but your second statement was the winner in that it made the point clear.
"Secondly, you'll notice that the object could actually be stationary in some reference frame, and that YOU are the one moving. So why should that object, just by coincidence, be at rest in your frame of reference? What makes you so special?"
 
  • #7
Oh, and I forgot to thank you. Thank you very much. This answers a question I've been pondering for quite a while, but have been unable to express in an understandable way. Thank you again.
 
  • #8
ZapperZ said:
Unfortunately, your question is actually a lot more "fundamental" and deeper than you think. What you are really asking is "why is there conservation of linear momentum?", and via Noether theorem, you are also directly asking "why does the classical empty space have translational symmetry?" (every conservation laws has an underlying symmetry principle).

We have no answers to those right now, the same way we have no answers to the many other "why's" in physics. Some think that physics doesn't address the why's, because the more you dig deeper into those reasons, you came up at the end with a description. But that is delving purely into philosophy.

Zz.
Thank you. I actually did understand that it was a deep question. The answer you later gave me, that there's no actual way to say that it's "moving" at all, due to the fact that in it's own frame it isn't, is the best answer I could get. Thank you.
 

1. What is momentum and why is it important?

Momentum is a fundamental concept in physics that measures the quantity of motion of a body. It is important because it helps us understand how objects move and interact with each other.

2. How is momentum carried or transmitted?

According to classical mechanics, momentum is carried by the movement of particles. In quantum mechanics, momentum is carried by waves or particles called quanta.

3. Can momentum be encoded or stored?

In classical mechanics, momentum cannot be encoded or stored as it is a property of an object's motion. However, in quantum mechanics, momentum can be encoded in the form of wavefunctions or quantum states.

4. How is momentum conserved in a closed system?

In a closed system, momentum is conserved, meaning that the total momentum of all objects in the system remains constant. This is known as the law of conservation of momentum.

5. How does momentum affect collisions between objects?

Momentum plays a crucial role in collisions between objects. In elastic collisions, momentum is conserved and the objects bounce off each other with equal and opposite momentum. In inelastic collisions, some of the momentum is lost due to deformation or heat, resulting in a decrease in the objects' combined momentum.

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