Question Detail

PHY 101 Rigid Body Dynamics Objective Question

Question

A thin rod of mass M and length L has a moment of inertia about an axis perpendicular to it through its center given by I = (1/12) M L². Using the parallel axis theorem, what is its moment of inertia about a parallel axis through one end?
Options
A (1/12) M L² + M (L/2)² = (1/3) M L²
Correct Answer
B (1/12) M L² + M L² = (13/12) M L²
C (1/12) M L² - M (L/2)²
D (1/12) M L² + M (L)²
Correct Answer

Option A is the correct answer.

Detailed Explanation

The parallel axis theorem states I = I_cm + Mh², where h is the perpendicular distance between the two parallel axes. Here, the distance from the center to the end is h = L/2. Therefore, I = (1/12) M L² + M (L/2)² = (1/12 + 1/4) M L² = (1/3) M L².

Hint

The parallel axis theorem relates the moment of inertia about any axis to that about a parallel axis through the center of mass.

Question Info