# What is the angular momentum of a rod with a mass of 5 kg and length of 4 m that is spinning around its center at  2 1 Hz?

##### 1 Answer
Aug 8, 2017

The angular momentum is $= 879.6 k g {m}^{2} {s}^{-} 1$

#### Explanation:

The angular momentum is $L = I \omega$

where $I$ is the moment of inertia

The moment of inertia of a rod, rotating about the center is

$I = \frac{1}{12} \cdot m {L}^{2}$

$= \frac{1}{12} \cdot 5 \cdot {4}^{2} = \frac{20}{3} k g {m}^{2}$

The angular velocity is

$\omega = 2 \pi f = 2 \cdot 21 \pi = 42 \pi r a {\mathrm{ds}}^{-} 1$

The angular velocity is

$L = \frac{20}{3} \cdot 42 \pi = 879.6 k g {m}^{2} {s}^{-} 1$