Point Transformations in the Lagrangian

In summary, point transformations in the Lagrangian refer to changes in coordinates that can simplify the equations of motion and reveal symmetries in a physical system. They are important in Lagrangian mechanics because they allow for easier solutions and identification of conserved quantities. These transformations result in a new Lagrangian that may have a simpler form and equivalent equations of motion. Some common examples include translations, rotations, and scale transformations. Point transformations are closely related to Noether's theorem, which connects symmetries and conserved quantities in a system.
  • #1
dynamicskillingme
27
0

Homework Statement


Hi, I'm working on understanding how a time independent point transformation
gif.gif
. effects the Lagrangian and to see how what values are co and contra variant.

Homework Equations


Would these be correct formulations, or have I overlooked something?

The Attempt at a Solution


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and
gif.gif

for Q = 0, from
gif.gif
 
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  • #2
dynamicskillingme said:
rtial%20L%7D%7B%5Cpartial%20q%7D%20%29%20%5Cfrac%7B%5Cpartial%20f%7D%7B%5Cpartial%20q*%7D%3D%200.gif
The left side seems ok. I don't know where the right side comes from, I mean the second factor of the left side.
 

Related to Point Transformations in the Lagrangian

1. What are point transformations in the Lagrangian?

Point transformations in the Lagrangian refer to changes in the coordinates used to describe a physical system. These transformations can help simplify the equations of motion and reveal underlying symmetries in the system.

2. Why are point transformations important in Lagrangian mechanics?

Point transformations are important in Lagrangian mechanics because they allow us to find new sets of coordinates that make the equations of motion easier to solve. They also help us identify conserved quantities, such as energy and momentum, which are crucial in understanding the behavior of a system.

3. How do point transformations affect the Lagrangian?

Point transformations affect the Lagrangian by changing the coordinates used to describe the system. This results in a new Lagrangian that may have a simpler form or reveal new symmetries. The equations of motion derived from this new Lagrangian will be equivalent to the original equations of motion, but may be easier to solve.

4. What are some examples of point transformations in the Lagrangian?

Some common examples of point transformations in the Lagrangian include translations, rotations, and scale transformations. These transformations can be applied to the coordinates of a system to simplify the equations of motion and reveal symmetries.

5. How do point transformations relate to Noether's theorem?

Point transformations are closely related to Noether's theorem, which states that for every continuous symmetry in a physical system, there exists a corresponding conserved quantity. Point transformations can help identify these symmetries and the associated conserved quantities, providing a powerful tool for understanding the behavior of a system.

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