# Moments of inertia

by darksyesider
Tags: inertia, inertias, moment, moments
 P: 55 Hi all, I was just wondering: suppose you have a setup of a torsion pendulum. You have a disk and ring attached, and you want to calculate the moment of inertia of the system. Do you just add the separate moment of inertia's of it? Like it would be: 1/2 mR^2 + 1/2M_2 (R_1^2+R_2)^2 = I_net ?? My friend was discussing this with me today, and he got something different, and I am confused on it. EDIT: actually i just found out how to do this. Please disregard (could a moderator please delete this post; i can't find the delete button)
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P: 12,488
 Do you just add the separate moment of inertia's of it?
Yes.

 Like it would be: 1/2 mR^2 + 1/2M_2 (R_1^2+R_2)^2 = I_net ??
Depends on the geomatry.

 EDIT: actually i just found out how to do this. Please disregard (could a moderator please delete this post; i can't find the delete button)
... try the "report" button.
OR you could try answering your own question and leaving it here - that way your efforts help others who google the same question.

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