The starting point is the action, denoted (calligraphic S), of a physical system. It is defined as the integral of the Lagrangian L between two instants of time t1 and t2 - technically a functional of the N generalized coordinates q = (q1, q2, ... , qN) which define the configurationof the system:
where the dot denotes the time derivative, and t is time.
Mathematically the principle is[19][20][21]
where δ (Greek lowercase delta) means a small change. In words this reads:[18]
The path taken by the system between times t1 and t2 and configurations q1 and q2 is the one for which the action is stationary (no change) to first order.
In applications the statement and definition of action are taken together:[22]
The action and Lagrangian both contain the dynamics of the system for all times. The term "path" simply refers to a curve traced out by the system in terms of the coordinates in the configuration space, i.e. the curve q(t), parameterized by time (see also parametric equation for this concept).
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1. What is the principle of least action in classical mechanics? |
2. How is the principle of least action related to the CSIR-NET Mathematical Sciences exam? |
3. Can you explain the concept of action in classical mechanics? |
4. How is the principle of least action related to the Lagrangian formulation of classical mechanics? |
5. Can you provide an example of how the principle of least action is applied in classical mechanics? |
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