Calculating the moment of inertia of a filled cylinder

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Homework Help Overview

The discussion revolves around calculating the moment of inertia for a filled cylinder, specifically in the context of an IB higher level physics extended essay. The cylinder is made of copper and contains a known mass of car engine oil, with the goal of analyzing its angular momentum as it rolls down a slope.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster expresses uncertainty about calculating the moment of inertia due to the presence of a viscous liquid inside the cylinder. Some participants inquire about the completeness of the problem statement and the data available for the experiment. Others suggest considering different models for the behavior of the oil within the cylinder.

Discussion Status

The discussion is ongoing, with participants exploring various interpretations of the problem. There is an acknowledgment of the need to develop equations that model the cylinder's behavior, and some guidance has been offered regarding potential models for the oil's motion.

Contextual Notes

The original poster notes that they have not received specific data for the experiment but can measure various parameters such as mass and radius. The constraints of the IB syllabus regarding moment of inertia are also mentioned, which may limit the original poster's familiarity with the topic.

Thynazgul
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Homework Statement


For my IB higher level physics extended essay I will have to calculate the angular momentum of a cylinder rolling down a slope. The cylinder is made out of copper and will be filled with a known mass of car engine oil. I think i can obtain the angular velocity fairly easily since it is just ω=2πF. My problem is with the moment of inertia of this cylinder.

Homework Equations


I know that the equation for moment of inertia is 1/2mr2 but this does not take into account that there is a viscous liquid inside of the cylinder. For angular momentum I will use L=I*ω.

The Attempt at a Solution


I have not tried much because the IB does not include moment of inertia in its syllabus so I am quite lost at the moment.
 
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Thynazgul said:

Homework Statement


For my IB higher level physics extended essay I will have to calculate the angular momentum of a cylinder rolling down a slope. The cylinder is made out of copper and will be filled with a known mass of car engine oil. I think i can obtain the angular velocity fairly easily since it is just ω=2πF. My problem is with the moment of inertia of this cylinder.

Homework Equations


I know that the equation for moment of inertia is 1/2mr2 but this does not take into account that there is a viscous liquid inside of the cylinder. For angular momentum I will use L=I*ω.

The Attempt at a Solution


I have not tried much because the IB does not include moment of inertia in its syllabus so I am quite lost at the moment.

It's not clear what information you have to work with. Can you post the complete text of the problem you are trying to solve?
 
SteamKing said:
It's not clear what information you have to work with. Can you post the complete text of the problem you are trying to solve?
The thing is that this is an experiment I have to perform. I have not been provided with any data but I can measure many things. I can measure mass, radius, velocities, pretty much anything I want. As for the problem, my teacher says that the point of this essay is to come of with a set of equations that can model the behaviour of a cylinder filled with oil rolling down a slope. I then compare my theoretical model with experimental data and see how accurate it was.
 
You can determine the moment of inertia of the empty cylinder. When it is filled with oil, and supposing it is is completely filled, you have two simple models for the behaviour of the oil: The oil does not rotate or the oil rotates together with the cylinder. Neither situation is real, but the experimental results will show which was closer to reality.
 
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