Question

What is the angular momentum of a rod with a mass of `8 kg` and length of `6 m` that is spinning around its center at `3 6 Hz`?

Answer 1

`1728\pi=5428.6` `kg.m^2/s`

Explanation:

The moment-of-inertia of a rod of mass `M` and length `L` rotating about its centre is `I=1/12 ML^2=1/12(8kg)(6m)^2=24kg.m^2`.

The angular frequency `\omega` is related to the frequency `f` as `\omega = 2\pi f=2\pi*(36Hz)=72\pi` rad/s,

Angular Momentum : The magnitude of Angular Momentum vector is `L=I\omega = I.2\pi f=(24 kg.m^2)*(72\pi)=1728\pi` `kg.m^2/s`