Re: classical physics - rod anchored to ground, rotational inertia
On further thought I was too quick on the second; you can't assume point masses.
Moment of Inertia of a disc is .5*m*R^2 (rotating perpendicular to plane disc is on)
I can't remember how to add moments of inertia so I guess I would just multiply them all by their distance from the center squared and sum. Not sure if that is right though...
I would get .5MR^2 + 3MR^2*r^2
R is radius of penny, r is distance of penny from center
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