Can Lagrangian Method be Applied to Solve Rocket Motion Equations?

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The discussion centers on the application of the Lagrangian method to solve rocket motion equations, highlighting difficulties in obtaining correct results. The original poster attempted to use Newton's laws but found inconsistencies when applying Lagrangian principles, particularly in eliminating equations. A key point of confusion is the interpretation of the variable "dm," which represents the small mass ejected from the rocket. Participants emphasize that the problem may not accurately describe rocket motion but rather a vessel expelling an object. The conversation underscores the complexities of applying Lagrangian mechanics in this context.
Abhishek11235
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Homework Statement


While solving equation of rocket motion with Newton's law in 1-d,I pondered to apply Lagrangian method on this. However, I didn't get correct result. Because I can eliminate last 2nd equation using last equation and get some other equation which is certainly not rockets motion.

Homework Equations

The Attempt at a Solution


The attempt is given in screenshot.
 

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Abhishek11235 said:
all variables and given/known data
What is ##dm## ? Dimension ?
 
BvU said:
What is ##dm## ? Dimension ?
A small mass ejected from rocket
 
So you don't describe a rocket but a vessel that throws some object off the ship in a backward direction ?
 

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