Speed of object falling from pulley

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Homework Help Overview

The problem involves a uniform circular shell rotating about a vertical axis, with a mass attached to a cord that passes over a pulley. The question focuses on determining the speed of the falling mass after it descends a certain distance, utilizing energy considerations.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the types of energy involved before and after the mass falls, specifically gravitational potential energy and kinetic energy. They explore the relationship between the falling mass and the rotating sphere.

Discussion Status

Some participants have offered guidance on identifying the forms of energy at play, while others are seeking clarification on the kinetic energies associated with the moving mass and sphere. The discussion is ongoing, with multiple aspects being explored without a clear consensus yet.

Contextual Notes

Participants express uncertainty regarding the specific types of kinetic energy involved and the overall energy transformations occurring in the system. There is a focus on understanding the implications of the mass falling and its effects on the connected components.

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A uniform circular shell of mass M and radius R rotates about a vertical axis on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I and radius r, and is attached to a small object of mass m. There is no friction on the pulleys axle; the cord does not slip. What is the speed of the object after it falls a distance h from rest? Use energy considerations.

I don't really know where to start, can anyone point me in the right direction?
 
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Sure. Use energy considerations.

What form of energy does the mass have before it falls, and how much?

What will be the forms of energy present after the mass has fallen "h"?
 
Last edited:
would it have gravitational potential energy?

Im not sure after..
 
Yes, gravitational potential, mgh right?

Now after this hanging mass has torqued the sphere, what TWO things are moving, and what kind of energies do they have? OK, what kind of kinetic energies do they have?
 
what two things are moving? the mass and the sphere?

What kind of kinetic energies? I have no clue?
 
Can someone please help me..this is the last question I need help solving!
 
the mass falls. what does that do to the string? what does the string do to the sphere?
so then what's the total kinetic energy?
 

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