Lagrangian about rolling disk on a horizontal plane

In summary, a Lagrangian is a mathematical function used in physics and engineering to describe the motion and energy of a system. In the context of a rolling disk on a horizontal plane, it takes into account factors such as rotational and translational motion and the interaction with the surface. The key variables in the Lagrangian for this system are the disk's angular and linear velocity, as well as the distance between its center of mass and the point of contact with the surface. The Lagrangian is used to derive the equations of motion for a rolling disk by applying the principle of least action, and it can also be applied to analyze other rolling objects in different situations.
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Homework Statement



upload_2017-3-18_21-39-22.png

Homework Equations

The Attempt at a Solution



This is the problem in Goldstein's classical mechanics exercise 1.11
I wonder why the solution doesn't consider rotational kinetic energy (1/2 I w^2)
So, L= T = 1/2mx^2 + 1/2 I w^2 .
 
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This problem was discussed here.
 
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Related to Lagrangian about rolling disk on a horizontal plane

1. What is a Lagrangian?

A Lagrangian is a mathematical function that describes the dynamics of a system. It is used in physics and engineering to analyze the motion of a system and its energy.

2. How is the Lagrangian used in the context of a rolling disk on a horizontal plane?

In the context of a rolling disk on a horizontal plane, the Lagrangian is used to describe the motion and energy of the disk. It takes into account factors such as the disk's rotational and translational motion, as well as its interaction with the surface it is rolling on.

3. What are the key variables in the Lagrangian for a rolling disk on a horizontal plane?

The key variables in the Lagrangian for a rolling disk on a horizontal plane are the disk's angular velocity, linear velocity, and the distance between the disk's center of mass and the point of contact with the surface.

4. How is the Lagrangian used to derive the equations of motion for a rolling disk on a horizontal plane?

The Lagrangian is used to derive the equations of motion for a rolling disk on a horizontal plane by applying the principle of least action. This principle states that the motion of a system will follow the path that minimizes the action, which is the integral of the Lagrangian over time.

5. Can the Lagrangian be used to analyze other rolling objects on a horizontal plane?

Yes, the Lagrangian can be used to analyze other rolling objects on a horizontal plane, such as spheres or cylinders. It can also be extended to analyze rolling objects on inclined planes or in more complex situations.

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