How to Calculate Moment of Inertia for a Solid Disk with Central Hole

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To calculate the moment of inertia for a solid disk with a central hole, first determine the mass using the density of aluminum (2.70 g/cm³) and the volume of the disk. The volume can be calculated by subtracting the volume of the hole from the volume of the entire disk. The moment of inertia can then be calculated using the formula I = M * r², where M is the mass and r is the radius of the disk. It is essential to convert units appropriately to ensure consistency in calculations. Understanding these steps will help solve similar problems effectively.
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Consider a solid disk made of aluminum with a central hole as shown in the figure - can't include...don't believe it's necessary. The external and internal diameters are found to be 13 inches and 0.6 inches. The disk is 0.5 inch thick. The density of aluminum is 2.70 g/cm3. Question:
Calculate the moment of inertia of this disk for rotations about its axle, in kg m2.

I have no idea how to determine the mass of a disk. I believe to determine the moment of inertia I use the formula Mxr^2

Formulas would be VERY much appreciated. I have several more problems on this pre-lab that are similar to this question. Thank you very much!
 
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Think of 2.7g/cm3 as a formula to find mass if you have volume in cm3. Therefore maybe start with finding the volume of the disk.
 

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