Rotational Kinematics (String attached to disk)

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Homework Help Overview

The discussion revolves around understanding the relationship between the angular acceleration of a flywheel, the downward acceleration of a block, and the radius of a ring in a rotational kinematics context. Participants are exploring the dynamics of a system involving a block connected to a flywheel via a string.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to relate the tension in the string to the forces acting on the block and is seeking guidance on how to initiate the problem. Some participants suggest using free-body diagrams (FBD) to analyze the forces involved, while others inquire about applying the concept of torque to the flywheel.

Discussion Status

Participants are actively engaging with the problem, with some offering hints and suggestions for starting points, such as drawing free-body diagrams and considering conservation of energy. There is a focus on understanding the forces acting on both the hanging mass and the spinning mass, indicating a productive exploration of the topic.

Contextual Notes

Participants are working with specific known data regarding the masses and dimensions of the components involved, but there may be uncertainties regarding the assumptions needed for the analysis, such as the effects of friction or the nature of the acceleration.

mattj150
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Homework Statement


Determine the relationship between the angular
acceleration of the flywheel, the downward acceleration of the block, and the radius of
the ring.

Known data:
Mass Ring: 1.420 kg
Radius Ring (Inside, then Outside): 5.10 cm, 6.325 cm
Mass Disk: 1.455 kg
Radius Disk: 11.45 cm
Mass Shaft: Negligable
Radius Shaft: 0.6 cm



Homework Equations



ω=ω0 + αt
f=ma

The Attempt at a Solution


I'm really lost on this, i assume that i need to calculate the tension the block places on the string (F=MA)? Could anyone give me a hint on how to get started on this.
 

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Welcome to PF;
Your wish is my command:
hint: draw free-body diagrams.

Though you could use conservation of energy and assume acceleration is constant.
 
I understand how to do the FBD for the hanging mass. The forces acting on it are simply Fg and Ft. How would i do a FBD for the spinning mass? Would i pick a point on the outer edge to do it for?
 
The tension force acts at a particular location on the flywheel - creating a torque. ##\tau=I\alpha##
 

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