Parallel Axis Theorem Experiment

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bobdylan
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Homework Statement



I am currently working on a physics experiment to confirm the parallel axis theorem. To do this, I have the following setup:

Diagram of a rotating platform apparatus: a horizontal black platform on a central cylindrical axle, a green disc sitting off-centre on the platform, a string running over a pulley at the right to a hanging blue mass, labelled Rotating Platform and Rotating Disc.

In this experiment I change the distance between the centre of the rotating disc and the central axis. I record the time for 5 complete rotations and use this to calculate the moment of inertia. I also measure the mass and the radius of the rotating disc. I then plot the moment of inertia against the square of the radius and this produces a straight line graph with a non-zero intercept.

How can I now use this data to confirm the parallel axis theorem?

Homework Equations



8d3ce730f104d2f33db72caec81b55ac055d27c2
and
00162d0dc4ecf6dade58332e43a0161f1185cf62


The Attempt at a Solution


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I think the graph should be of the form:

Itotal = Iapparatus + Idisk + mr^2

Is this correct?

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Attachments
  • Equation written as I = mr^2, with the text 'I = mr^2.' shown on a white background, likely the moment of inertia of a point mass at distance r from the axis.
    upload_2018-3-18_20-13-15.png
    409 bytes · Views: 600
  • Diagram of a rotating platform apparatus: a horizontal black platform on a central cylindrical axle, a green disc sitting off-centre on the platform, a string running over a pulley at the right to a hanging blue mass, labelled Rotating Platform and Rotating Disc.
    aT7vs.png
    2.7 KB · Views: 1,719
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Hello Robert, :welcome:
bobdylan said:
Itotal = Iapparatus + Idisk + mr^2
Is correct. Now you need something to relate the time for five revolutions with ##I_{\rm total}##.