Are momentum and centripetal acceleration related somehow?

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Discussion Overview

The discussion centers on the relationship between momentum and centripetal acceleration, exploring whether they are connected through velocity or other factors. Participants examine the nature of this relationship in both theoretical and conceptual terms.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that centripetal acceleration is related to the change in velocity associated with the change in direction, which also affects momentum.
  • One participant notes that centripetal acceleration is proportional to the square of the velocity divided by the radius, questioning how this relates to momentum.
  • Another participant suggests that while both centripetal acceleration and momentum depend on velocity, this does not imply a direct relationship between them, as it could make the question vague.
  • It is mentioned that if the velocity increases by a factor of 2, linear momentum increases by the same factor, while centripetal acceleration increases by a factor of 4.
  • Some participants argue that the velocity in centripetal acceleration and momentum is the same but plays different roles, with momentum being linear and centripetal acceleration being quadratic.
  • There is a discussion about whether the square of the velocity in centripetal acceleration can be derived from linear momentum, with some suggesting that while it can be done, it may not be meaningful in standard definitions.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the relationship between momentum and centripetal acceleration. While some acknowledge a connection through velocity, others argue that the relationship is not straightforward and remains somewhat ambiguous.

Contextual Notes

Participants highlight the complexity of relating different physical quantities and the potential for ambiguity in defining their relationships. The discussion reflects varying interpretations of how velocity influences both momentum and centripetal acceleration.

Sundown444
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I have been wondering, simple question, really: What is the relationship between momentum and centripetal acceleration, if there is one? Is there a relationship in terms of velocity, maybe, or is there none whatsoever?
 
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An acceleration is a rate of change of velocity, remembering that velocity involves both magnitude and direction. In the usual case, centripetal acceleration is related to the change in velocity associated with the change in direction. When you change the direction of motion, you change the momentum of the body as well. So, yes, they are related.
 
I see. Well, I have one more question. Centripetal Acceleration is proportional to the square of the velocity divided by the radius. How is the square of the velocity related to the velocity in momentum, if it is?
 
Dr.D's answer is neat, but if you're looking for something more I think you may want to clarify what you mean by being related; both of them have a dependency on velocity, yes, but that would make every cinematic quantity somehow related with each other, thus making your question a bit vague.
Sundown444 said:
I see. Well, I have one more question. Centripetal Acceleration is proportional to the square of the velocity divided by the radius. How is the square of the velocity related to the velocity in momentum, if it is?
Not sure if i get what you are asking here, but consider a point mass in motion along some curve: every single point P on the curve can be locally approximated by a circle of radius R_P (see osculating circle), so at every point you can compute a value for your centripetal acceleration a_c = \frac{v^2}{R_P}, so if you remember that linear momentum is q = mv you'll note that if velocity increase by a factor of 2, linear momentum will increase by the same factor, while centripetal acceleration will increase by a factor of 2^2=4.
Likewise, if you change the centripetal acceleration acting on the body by a factor k (without changing its istantaneous radius of curvature), its speed, and therefore its linear momentum, will change by a factor \sqrt{k}
 
Sundown444 said:
How is the square of the velocity related to the velocity in momentum
By a power of 2.
 
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mastrofoffi said:
Dr.D's answer is neat, but if you're looking for something more I think you may want to clarify what you mean by being related; both of them have a dependency on velocity, yes, but that would make every cinematic quantity somehow related with each other, thus making your question a bit vague.
Not sure if i get what you are asking here, but consider a point mass in motion along some curve: every single point P on the curve can be locally approximated by a circle of radius R_P (see osculating circle), so at every point you can compute a value for your centripetal acceleration a_c = \frac{v^2}{R_P}, so if you remember that linear momentum is q = mv you'll note that if velocity increase by a factor of 2, linear momentum will increase by the same factor, while centripetal acceleration will increase by a factor of 2^2=4.
Likewise, if you change the centripetal acceleration acting on the body by a factor k (without changing its istantaneous radius of curvature), its speed, and therefore its linear momentum, will change by a factor \sqrt{k}

I see. Well, beyond the square root of velocity in centripetal acceleration and such, there wasn't much else I was asking for, if anything at all. So, the velocity squared in centripetal acceleration is independent from the velocity in momentum, I take it?
 
Sundown444 said:
I see. Well, beyond the square root of velocity in centripetal acceleration and such, there wasn't much else I was asking for, if anything at all. So, the velocity squared in centripetal acceleration is independent from the velocity in momentum, I take it?
No, how can the velocity be independent from itself? I mean, it is the same velocity we are talking about, it just plays a different role in the 2 quantites, momentum being linear in v while centripetal acceleration is quadratic. In fact, as I showed you, with fixed mass and trajectory a change in centripetal acc implies a change in linear momentum and viceversa.
If what you are asking is "is the v^2 in the centripetal acceleration directly derivable from the linear momentum?" then for sure you can find some fancy way to derive it like that(consider a body under action of centripetal force, note that F = dq/dt, etc..) but it would be hardly meaningful with respect to the standard way of defining those quantities.
 
mastrofoffi said:
No, how can the velocity be independent from itself? I mean, it is the same velocity we are talking about, it just plays a different role in the 2 quantites, momentum being linear in v while centripetal acceleration is quadratic. In fact, as I showed you, with fixed mass and trajectory a change in centripetal acc implies a change in linear momentum and viceversa.
If what you are asking is "is the v^2 in the centripetal acceleration directly derivable from the linear momentum?" then for sure you can find some fancy way to derive it like that(consider a body under action of centripetal force, note that F = dq/dt, etc..) but it would be hardly meaningful with respect to the standard way of defining those quantities.

Yeah, that is what I meant to say, the playing a different role part. My bad. Sorry about that.
 

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