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Why do we use L for Angular Momentum?

  1. Mar 10, 2009 #1
    Why do we use L for angular momentum? Why not M or some other letters?
  2. jcsd
  3. Mar 10, 2009 #2
    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.
  4. Mar 10, 2009 #3


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    Science Advisor

    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')
  5. Mar 10, 2009 #4
    Perhaps it stands for Leonhard Euler, "the master of us all" whose description of rotational kinematics is still in use today.
  6. Mar 10, 2009 #5
    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.
  7. Mar 10, 2009 #6
    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! :rofl:
  8. Mar 10, 2009 #7
    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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