Question

A circle is cut out of a uniform piece of plywood. How does the rotational inertia measured around a point on its outer edge
compare with the rotational inertia about its central axis?
a. The two rotational inertias are the same.
b. The rotational inertia about its edge is twice as great as it is about its center.
c. The rotational inertia about its edge is three times as great as it is about its center.
d. The rotational inertia about its edge is half as great as it is about its center.
e. The rotational inertia about its edge is one third as great as it is about its center.
Also the reason for it.

Answer 1

The parallel axis theorem applies
Inew=Iold+Md^2 d is the distance axis of rotation moved.
Since I old was 1/2 Mr^2, and now it is Inew=3/2 Mr^2....answer C applies