As of May 31, 2023, we have updated our Code of Conduct.

# Questions tagged [variational-principle]

Any of several principles that find the physical trajectory of a system by minimizing or maximizing some value computed over the proposed path (for instance geometric optics can be reproduced by insisting on a minimum time principle).

1,040 questions
Filter by
Sorted by
Tagged with
10 views

61 views

### Is the principle of stationary action a deterministic or probabilistic principle? [duplicate]

I was reading Why the Principle of Least Action? and the top voted answer says You can go further mathematically by learning the path integral formulation of nonrelativistic quantum mechanics and ...
1 vote
38 views

1 vote
42 views

### How to derive the free rigid body equations from Euler-Lagrange? [closed]

I'm trying to retrieve the equations of motion for a free rigid body: $$I(t)\dot{\omega}(t)+\omega(t)^T \times (I(t)w(t)) = 0$$ where $$I(t)=R(t)I_{0}R(t)^T$$ I know that Euler-Lagrange equations ...
I was trying to understand this section of a Wikipedia article: $$0 = \delta \int \sqrt{2T} d\tau = \int \frac{\delta T}{\sqrt{2T}} d\tau = \frac{1}{c} \delta \int T d\tau$$ For the life of me, ...