Understanding Moments in Math and Physics: A Beginner's Guide

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Discussion Overview

The discussion revolves around the concept of "moment" as it appears in both mathematics and physics. Participants explore various interpretations and applications of the term, including its use in different contexts such as mechanics and statistical distributions.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes a moment as a twisting tendency resulting from a force applied at a distance from an axis of rotation.
  • Another participant introduces the concept of the nth moment of a distribution, defined by an integral involving a density function.
  • There is a question about the general usage of the term "moment" and whether magnetic moments are equivalent to mechanical moments in classical mechanics.
  • Several types of moments in physics are listed, including linear moment, angular moment, moment of a force, moment of inertia, and dipole moments.
  • A distinction is made between "moment" and "momentum," with clarification that linear moment refers to linear momentum (p = mv).
  • Participants express uncertainty about the terminology and its implications, with some suggesting that the term "moment" is used broadly in physics.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions and distinctions between different types of moments. There are competing views regarding the relationship between various moments and the terminology used in physics.

Contextual Notes

Some participants note the potential confusion between "moment" and "momentum," indicating a need for clarity in definitions. The discussion also highlights the informal nature of the conversation, with participants sharing personal insights and humor.

Who May Find This Useful

This discussion may be useful for beginners seeking to understand the concept of moments in both mathematics and physics, as well as for those interested in the nuances of terminology in these fields.

Mathgician
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Don't flame me please:cry: What is a moment? I learn it in math and in physics , I never really got either enough experience in it or never came to a realization.
All you physics whiz, please help me understand what it is.:frown:
 
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Its a twisting tendency that occurs when you have a force applied at some distance from an axis of rotation.
 
There's at least one other common usage of the word moment
the nth moment of a distribution is defined as

[itex]\int \rho(x) x^n dx[/itex]
 
so why is this word used in such general terms? Is magnetic moment same as mechanical moment in classical mechanics in general?
 
I'll tell you in just a moment...

I think almost all use of the term 'moment' is related to some sort of integral like the one in my post. You'd have to study the equations to see if this is true.
 
Mathgician said:
so why is this word used in such general terms? Is magnetic moment same as mechanical moment in classical mechanics in general?

Yes, a moment is a moment is a moment.
 
There are several "moments" in physics. When a physicist does not how to name a physical quantity, he christens it "moment something". There are (at least):
linear moment
angular moment
moment of a force
moment of inertia
dipole moments (magnetic and electric)

cyrusabdollahi described the moment of a force.
I think that the one you are asking is the linear moment. This is the product of the mass of the object times its speed. p = mv.
When you are hit by a moving object (I do not talk about hurting or killing hits!) it is the moment of the object that will overthrow you or not. Not the speed or the mass alone, but the product of both.
For the other moments you can begin reading the corresponding entry in wikipedia and post your questions if there is still something unclear.
 
lpfr said:
There are several "moments" in physics. When a physicist does not how to name a physical quantity, he christens it "moment something".

Physicists can also be a 'she'.
 
christianjb said:
Physicists can also be a 'she'.

:smile: :smile: :smile: :smile: :smile:

Thanks lpfr, I think your explanation was what I was seeking, anyone elese have any other insights I would appreciated very much. Funny Christianjb, very funny. Do you mind If I ask you what your gender is?
 
Last edited:
  • #10
lpfr said:
There are (at least):
linear moment
angular moment[/color]
moment of a force
moment of inertia
dipole moments (magnetic and electric)

I think here you mean "linear momentum" and "angular momentum." You have then gone on to give a description of linear momentum, when the OP asks "what is moment;" not "what is momentum."
 
  • #11
cristo said:
I think here you mean "linear momentum" and "angular momentum." You have then gone on to give a description of linear momentum, when the OP asks "what is moment;" not "what is momentum."

Yeah p or mv is momentum, not moment
 
  • #12
Mathgician said:
:smile: :smile: :smile: :smile: :smile:

Thanks lpfr, I think your explanation was what I was seeking, anyone elese have any other insights I would appreciated very much. Funny Christianjb, very funny. Do you mind If I ask you what your gender is?

I'm male, but I know some excellent female physicists.
 

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