A thin, uniform rod is bent into a square of side length a.

If the total mass is M , find the moment of inertia about an axis through the center and perpendicular to the plane of the square. Use the parallel-axis theorem.
Express your answer in terms of the variables M and a.

PLEASE HELP WITH A THOROUGH EXPLANATION PLEASE!!!

3 answers

We may disagree on thorough explaination. I am not doing students work for them.

Look at the square. It has sides a/4, and M/4. Now if you look at it from the center, the moment of inertia could be calculated from the I of any of those rods, moved with the parallel axis theorm to the center (a distance of a/8), then multiplyied by 4 due to all the rods contribution.

I will be happy to critique your thinking or work. Repost if if you need help.
so would I = ma^2? i am confused
billy