Calculating Rod Movement with Lagrangian Mechanics: Shear Modulus & Mass Ratios

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Homework Help Overview

The discussion revolves around calculating the movement of a rod using Lagrangian mechanics, specifically focusing on the shear modulus of the material and the mass ratio between two blocks. The original poster seeks assistance in formulating the Lagrangian and understanding the relationship between the forces acting on the rod and the block it is attached to.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the formulation of the Lagrangian and the connection between the shear modulus and the forces acting on the rod. Questions are raised about how to relate the impulse applied to the larger block to the motion of the rod.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the problem setup and exploring different aspects of the mechanics involved. Some guidance has been offered regarding the relationship between the forces and the rod's movement, but no consensus has been reached on the specific approach to take.

Contextual Notes

There is a mention of the original poster's assumption that the mass of the block (M) is significantly greater than the mass of the rod (m), and the angle (θ) is set to zero. The need for additional information or resources is also noted.

danesh
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Hi!
I want to calculate the movement of the rod in the picture, but I don't know how to put up the Lagrangian for the problem.
I have the Shear modulus, [tex]\mu[/tex], for the material and M>>m and [tex]\theta = 0[/tex]. I need the Lagrangian and from there on I think I can manage with the calculations myself.

Thanks
 

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Can you post the wording of the problem.
 
Gamma said:
Can you post the wording of the problem.
Well, I have come up with the problem myself.
What I am trying to get is an equation for the motion of the rod, or cantilever if you will. My problem is that I am not sure how to relate the force influencing the heavy block the rod is attached to, to the rod.
I think I need to make a connection between the Shear modulus, or the elasticity modulus of the material the rod and the block is made of to the force which is transferred to the rod.

I will settle for some help using usal mechanics on how the force is transferred from the block to the rod.

Thanks
 
Ok, let me refrase my question a bit.
Can somebody tell me how the rod goes about to "sway" when a impulse is applied on the bigger block with mass M?
If you know a book or a homepage, which you could refer me to for this problem, I would apperciate that as well.
 

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