How Do You Apply Lagrange Multipliers to a Rolling Disk and Fixed Bar System?

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Homework Help Overview

The discussion revolves around applying the Lagrange multipliers method to derive differential equations for a system involving a rolling disk and a fixed bar. The original poster seeks assistance with constraints and the Lagrange multiplier equation.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to derive the kinetic and potential energy for the system and is specifically looking for help with the constraints involved in the Lagrange multiplier method. Some participants question the nature of the constraints, with one suggesting it may not be a nonholonomic constraint. Others inquire about the relationship between the coordinates involved.

Discussion Status

The discussion is ongoing, with participants exploring the relationship between the coordinates and the nature of the constraints. Some guidance has been offered regarding the geometric aspects of the problem, but no consensus has been reached yet.

Contextual Notes

There is mention of potential confusion regarding the type of constraint (nonholonomic vs. holonomic) and the specific relationship between the coordinates β and θ, which remains unclear.

deniz120
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Homework Statement



Hi all, I need to derive differantial equations of system with lagrange multiplier method, a disk is rolling and a bar is fixed onto the point of a disk

[PLAIN]http://img130.imageshack.us/img130/1669/adsziss.jpg
By deniz120 at 2010-05-31


Homework Equations





The Attempt at a Solution


please check my solution below, I derived T and V for Lagrange, all I need is help for constaints, lagrange multiplier equation. Thanks in advance:)

[PLAIN]http://img263.imageshack.us/img263/3659/tarama0001r.jpg
By deniz120 at 2010-05-31]
 
Last edited by a moderator:
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unfortunately nothing, I guess there is nonholonomic constraint
thanks
 
It's not a nonholonomic constraint.

You have only two coordinates, β and θ. How are they related?
 
I guess you are right but that is the exact question that I m looking for the answer, how are they related:)
 
Really? It's basic geometry. Consider the height of point B.
 

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