Acceleration of Center of Mass

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Homework Help Overview

The discussion revolves around a model involving two slender rods connected by a pin and anchored at one end, with a focus on analyzing the acceleration of the center of mass of one of the rods as it rotates with a constant angular velocity. The original poster is tasked with demonstrating this behavior through graphs in Matlab while considering the effects of changing angles.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster questions whether the center of mass of the rod would have zero acceleration given a constant angular velocity. Some participants seek clarification on the definitions of variables such as theta, alpha, and the role of the horizontal slider in the setup.

Discussion Status

Participants are actively engaging with the problem, with some providing requests for clarification and others pointing out potential misunderstandings regarding the definitions of angular and linear acceleration. There is an ongoing exploration of the implications of the setup and the relationships between the variables involved.

Contextual Notes

There are indications of confusion regarding the variable definitions and the physical principles at play, particularly concerning the nature of acceleration in circular motion. The discussion highlights the importance of clear communication of variable meanings in the context of the problem.

Ian Blankenship
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Thread moved from the technical forums, so no Homework Template is shown
I have a model of two slender rods (call them OA and AB) connected with a pin at A, anchored at O with a pin, and attached to horizontal slider at B. I am supposed to show graphs of different variables in Matlab as the angle theta changes. One of these steps is to show the acceleration of the center of mass of link OA. It is given that link OA has a constant angular velocity 'omega' in the CW direction. Dumb question, but if the rod has constant angular velocity, would a point half way down this link (center of mass) also have zero acceleration? (Note, I am asked to find linear acceleration, i.e. a=alpha/r)
 
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Can you draw a diagram or something? It's not clear what theta is, and what a horizontal slider is, and what alpha is.
 
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Apologies, here is an image of the problem.
dynamicsdiagram.PNG


This is the same image as what is used in my problem, except that T direction (torque I assume) is placed on this diagram.
 
This should be in the homework forum.
 
Ian Blankenship said:
Note, I am asked to find linear acceleration, i.e. a=alpha/r
Note: this looks utterly wrong, dimensionally. Unless you tell us that alpha is the acceleration and a the angular acceleration. That's what 's so useful about the template in the homework fora: people can understand what you type if you explain the variable names.

And: something that moves in a circle does not have zero acceleration (Newton 1).
 

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