- #1
theBEAST
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Homework Statement
Homework Equations
I_a = I_G + md^2
The Attempt at a Solution
I tried using the parallel axis theorem to find the moment of inertia about the axis.
In the formula sheet they give the moment of inertia of a hemisphere:
I_G = 0.259mr^2, where d, the distance from the center is equal to (3r/8).
Thus to find the inertia about the axis we will have to solve
I_a = 0.259mr^2 + m(3r/8)^2
This ends up giving me 2mr^2/5 which is not the answer... However I still think this is the correct answer. This is because I_a = mr^2/5 = 0.2mr^2 (which is the answer according to the prof) is less than the moment at the center I_G = 0.259mr^2. According to the parallel axis equation I_a = I_G + md^2, I_a must be larger than I_G not smaller...