Why Is Action Defined as Energy Minus Potential Energy in Physics?

[Andrea2]

Hi! I'm new of this forum and I'm searching a way to understand why the action is E-U, but in this moment i don't know how to do...ther's someone who can help me? Thank you

 

[hunt_mat]

It turns out that if you set the Lagrangian to be T-V then you recover Newton's laws of motion.

 

[Cleonis]

Hi! I'm new of this forum and I'm searching a way to understand why the action is E-U, but in this moment i don't know how to do...ther's someone who can help me? Thank you

The question is of course: why does T-V recover Newton's laws of motion? As it turns out: that question is not hard to answer.

An abbreviated discussion is in post https://www.physicsforums.com/showpost.php?p=2975435&postcount=10" of the recent thread called 'Lagrangian'.

A more detailed version (more diagrams) is available on my website: http://www.cleonis.nl/physics/phys256/least_action.php" .

 

[Andrea2]

ok, thank you very much!