- #1
PennDreamer
- 1
- 0
Why do we use L for angular momentum? Why not M or some other letters?
Why do we use L for Angular Momentum?
- Context: High School
- Thread starter PennDreamer
- Start date
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Discussion Overview
The discussion revolves around the question of why the letter "L" is used to represent angular momentum in physics, exploring the origins and conventions behind this notation. Participants delve into historical context, personal experiences, and the arbitrary nature of symbol selection in scientific notation.
Discussion Character
- Exploratory, Conceptual clarification, Debate/contested
Main Points Raised
- Some participants suggest that the choice of "L" may have historical significance, possibly linked to figures like Leonhard Euler.
- Others note that "L" is not derived from the words for 'angular momentum' in other languages, nor was it a notation used by Newton.
- A participant mentions that different texts may use various symbols for angular momentum, such as "J" or "h," indicating the arbitrary nature of symbol selection.
- One participant humorously proposes that "L" could stand for "Langular momentum," though this is acknowledged as a joke.
- Concerns are raised about the lack of consistent definitions for symbols among participants, which could lead to confusion.
Areas of Agreement / Disagreement
Participants express a mix of viewpoints, with no consensus on the definitive reason for using "L" for angular momentum. The discussion includes both historical speculation and personal anecdotes about symbol usage.
Contextual Notes
Some participants reference specific texts and their notation choices, highlighting that conventions may vary across different educational materials.
Who May Find This Useful
This discussion may be of interest to students and educators in physics, particularly those curious about the conventions of scientific notation and the historical context of physical symbols.
- #2
Winzer
- 597
- 0
Because it is secretly called Langular momentum.
Not really.
That's a good question, I'm sure it's a convention that has it's story.
Not really.
That's a good question, I'm sure it's a convention that has it's story.
- #3
alxm
Science Advisor
- 1,848
- 9
Well, it's not a letter Newton used.
It's not an abbreviation of the words for 'angular momentum' in French or German.
I've got "Traité de physique" by Biot at home. Maybe I can find it there. (it helped me find out why the magnetic field is 'B')
It's not an abbreviation of the words for 'angular momentum' in French or German.
I've got "Traité de physique" by Biot at home. Maybe I can find it there. (it helped me find out why the magnetic field is 'B')
- #4
confinement
- 192
- 0
Perhaps it stands for Leonhard Euler, "the master of us all" whose description of rotational kinematics is still in use today.
- #5
Bob S
- 4,662
- 8
In my mechanics book (Theoretical Mechanics, Becker, 1954), J is used as the vector cross product of r and m dr/dt (hence angular momentum), and L is used as dJ/dt (hence torque). Later on, L is used as the Lagrangian L= T - V, and H as the Hamiltonian H = T + V.PennDreamer said:
- #6
Ofey
- 75
- 0
Winzer said:
I am sorry if this is considered as spam and I shall take the fall for that. This was too good of a joke to forgotten just like that. Great!
- #7
Dr.D
- 2,411
- 723
I think it is just an arbitrary choice that some one made. When I was in school we used h for angular momentum in classical physics. It really makes no difference as long as you define your symbols, which very few people here do.
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