I need to derive the moment of inertia of a thin rod with its axis of rotation at the end of the rod. http://ift.tt/1eG9r2u
The third one.
2. Relevant equations
I = mr^2
3. The attempt at a solution
I completely understand how the moment of inertia is mL^2/3, but what I don’t understand is why linear density is used. M/L. Shouldn’t it be volume density, or area density at the very least since a thin rod is 3D?