# Math Help - Moment of Inertia-physics

1. ## Moment of Inertia-physics

A rigid body in the shape of the letter E is made by joining together five identical slender metal rods, each of mass M=3.25 kg and length L= 0.480 m.

E
Calculate the moment of inertia if this shape rotates about an axis that is perp to the plane of the figure E and passes through the right end of the center bar of the letter.

I dont know the formula needed for I or how to solve this. My professor hinted that we should consider each bar separately.

2. The moment of inertia for a thin rod of mass M and length L about a perpendicular axis through one end of the rod is $\frac{1}{3}ML^2$, while the moment of inertia for a thin rod about a perpendicular axis through its center of mass is MATH]\frac{1}{12}ML^2[/tex] (see here). Combine these with the Parallel axis theorem to find the moment of inertia of each rod about the desired axis; then sum these values.

--Kevin C.