Both sides previous revision Previous revision Next revision | Previous revision | ||
theories:classical_mechanics:lagrangian [2018/05/06 11:31] jakobadmin [Concrete] |
theories:classical_mechanics:lagrangian [2018/10/11 14:12] (current) jakobadmin [Abstract] |
||
---|---|---|---|
Line 19: | Line 19: | ||
\end{equation} | \end{equation} | ||
- | [{{ :theories:trajectories.png?nolink&400|Source: Lectures on Classical Mechanics by [[http://math.ucr.edu/home/baez/classical/texfiles/2005/book/classical.pdf|John C. Baez]]}}] | + | {{ :theories:classical_mechanics:lagrangianpfad.png?nolink&400|}} |
The basic idea is now that nature causes | The basic idea is now that nature causes | ||
particles to follow the trajectories with the //least// amount of action. | particles to follow the trajectories with the //least// amount of action. | ||
- | In the image on the right-hand side this could be the solid line denotes by $q$. Another path is shown as a dashed line and denoted by $q(s)$. The Lagrangian approach assigns to each path a quantity called action as defined above and then tells us that the correct path that an object really follows is the path with minimal action. In our example the path $q$ could have an action of $3$ and the path $q_s$ an action of $5$. Hence, path $q$ is correct and not path $q_s$. | + | In the image on the right-hand side this could be the solid line denotes by $q$. Another path is shown as a dashed line and denoted by $q(s)$. |
+ | |||
+ | The Lagrangian approach assigns to each path a quantity called action as defined above and then tells us that the correct path that an object really follows is the path with minimal action. In our example the path $q$ could have an action of $3$ and the path $q_s$ an action of $5$. Hence, path $q$ is correct and not path $q_s$. | ||
Line 208: | Line 210: | ||
* The best book on Lagrangian mechanics is The Lazy Universe by Coopersmith | * The best book on Lagrangian mechanics is The Lazy Universe by Coopersmith | ||
+ | * Many problems with solutions are collected in [[https://archive.org/details/SchaumsTheoryAndProblemsOfTheoreticalMechanics|Schaum's Outline of Theory and Problems of Theoretical Mechanics]] by Murray R Spiegel | ||
<tabbox Abstract> | <tabbox Abstract> | ||
Lagrangian mechanics can be formulated geometrically using [[advanced_tools:fiber_bundles|fibre bundles]]. | Lagrangian mechanics can be formulated geometrically using [[advanced_tools:fiber_bundles|fibre bundles]]. | ||
Line 220: | Line 223: | ||
---- | ---- | ||
+ | * [[https://core.ac.uk/download/pdf/4887416.pdf|Lectures on Mechanics]] by Marsden | ||
* See page 471 in Road to Reality by R. Penrose, page 167 in Geometric Methods of Mathematical Physics by B. Schutz and http://philsci-archive.pitt.edu/2362/1/Part1ButterfForBub.pdf. | * See page 471 in Road to Reality by R. Penrose, page 167 in Geometric Methods of Mathematical Physics by B. Schutz and http://philsci-archive.pitt.edu/2362/1/Part1ButterfForBub.pdf. | ||