- #1

member 392791

I am confused about the terminology moment, specifically that there is a 1st moment and 2nd moment. What does moment even mean, and why does it have numbers associated with them?

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter member 392791
- Start date

- #1

member 392791

I am confused about the terminology moment, specifically that there is a 1st moment and 2nd moment. What does moment even mean, and why does it have numbers associated with them?

- #2

Drakkith

Staff Emeritus

Science Advisor

- 21,136

- 4,976

What context is it being used in?

- #3

member 392791

torques

- #4

jhae2.718

Gold Member

- 1,161

- 20

If so, these are relations based on the distributions of points in an area, e.g.:

1

##S_x = \int_A y {\rm d}A##

(This is often used to find the centroid of an object.)

2

##I_x = \int_A y^2 {\rm d}A##

(This is an important quantity in strength of materials/Euler-Bernoulli beam theory.)

- #5

member 392791

- #6

jhae2.718

Gold Member

- 1,161

- 20

Moment of inertia can also have multiple meanings: it can be a measure of how mass is distributed about an axis (mass moment of inertia; used in dynamics) or a measure of how area is distributed about an axis (in strength of materials). This latter definition is also known as the Second Moment of Area.

You can think of moments as being quantities measured about an axis or surface. More abstractly, in mathematics a moment is a measure about a set of points (this is ultimately where the term comes from). The multiplicity of meaning of the term "moment" can get confusing when you're first exposed to it.

- #7

SteamKing

Staff Emeritus

Science Advisor

Homework Helper

- 12,796

- 1,669

http://en.wikipedia.org/wiki/Moment_(physics)

Don't worry, there's some moments associated with mathematics, particularly statistics.

The concept is a general one. You can even find it used in thermodynamics.

Share: