**Sample Problem**

Shows a rigid body consisting of two particles of mass m connected by a rod of length L and negligible mass.

(a) What is the rotational inertia leorn of this body about an axis through its center of mass. perpendicular to the rod as shown?

SOLUTION: The Key Idea is that because we have only two particles with mass. we can find the body’s rotational inertia leorn by using rather than by integration. For the two particles. each at perpendicular distance ~L from the rotation axis,

(b) What is the rotational inertial of the body about an axis through the left end of the rod and parallel to the first axis?

SOLUTION: This situation is simple enough that we can find I using either of two Key Ideas. The first is identical to the one we used in (a). The only difference here is that the perpendicular distance.

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