Rotational Inertia of a Pulley System

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SUMMARY

The discussion focuses on calculating the rotational inertia of a pulley system, specifically using the equations for kinetic energy, linear velocity, and torque. Key equations include Kinetic Energy = 0.5 I w^2, v = r * w, and torque = Inertia * angular acceleration. Participants emphasize the relationship between angular velocity and linear velocity, highlighting the need to determine the loss in potential energy (PE) as the pulley completes one revolution. The conversation aims to clarify how to derive angular speed from linear speed and calculate the kinetic energies of both the masses and the pulley.

PREREQUISITES
  • Understanding of rotational dynamics and inertia
  • Familiarity with the concepts of kinetic energy and potential energy
  • Knowledge of angular velocity and linear velocity relationships
  • Basic grasp of torque and angular acceleration
NEXT STEPS
  • Study the derivation of the relationship between linear speed and angular speed in pulley systems
  • Explore the calculation of potential energy loss in mechanical systems
  • Learn about the conservation of energy principles in rotational motion
  • Investigate the application of torque in real-world pulley systems
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Students in physics courses, mechanical engineers, and anyone studying rotational dynamics and energy conservation in pulley systems.

Derpity Derp
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Homework Statement



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Homework Equations



Kinetic Energy = 0.5 I w^2
v = r * w
torque = Inertia * angular acceleration

The Attempt at a Solution



That's the problem. I have no idea where to start. I assume that the end goal is to find the angular velocity, and convert to linear velocity, but I don't know how to go about doing that. Any hints are appreciated.
 
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Derpity Derp said:
I assume that the end goal is to find the angular velocity, and convert to linear velocity,
Not exactly. Both are unknown, but they are related by the equation you quote.
What will be the loss in PE as the pulley executes one revolution?
If the linear speed of the masses is v, what is the angular speed of the pulley?
In terms of v, what are the KEs of the masses and the pulley?
 

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