How Do You Calculate the Moment of Inertia for a Disk Rotating About Its Edge?

AI Thread Summary
To calculate the moment of inertia for an 8 kg, 40 cm diameter disk rotating about its edge, the initial formula for inertia at the center is I = 1/2 MR^2. The parallel axis theorem is then applied to find the moment of inertia about the edge, which involves adding the inertia at the center (I_cm) to the product of mass (M) and the square of the distance (d) from the center to the edge. The correct formula becomes I = I_cm + Md^2, where d is the radius of the disk. This approach allows for accurate calculation of the moment of inertia for the specified rotation. Understanding these principles is crucial for solving related physics problems.
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Homework Statement


What is the moment of inertia of an 8 kg, 40 cm diameter disk for rotation through the edge of the disk?


Homework Equations


I = \frac{1}{2}MR^2


The Attempt at a Solution



Inertia at the center of the disk would be I = \frac{1}{2}MR^2, right? I'm not sure what the right equation for inertia at a point on the edge of a disk would be.
 
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Apply the parallel axis theorem to find the moment of inertia about a parallel axis a distance d from the centre of mass:

I = I_{cm} + Md^2AM
 

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