# A solid disk, spinning counter-clockwise, has a mass of 1 kg and a radius of 3 m. If a point on the edge of the disk is moving at 9 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

Angular Momentum L=13.5" "kg*m^2/("second")
Angular Velocity $\omega = 3 \text{ } \frac{r a d}{\sec}$

#### Explanation:

Angular Momentum $L = I \cdot \omega$

where $I = \frac{1}{2} \cdot m {r}^{2} \text{ }$Moment of inertia

$I = \frac{1}{2} \cdot \left(1\right) \left({3}^{2}\right) = 4.5 \text{ } k g \cdot {m}^{2}$

Angular Velocity

$\omega = \frac{v}{r}$

omega=9/3=3" "(radian)/("second")

Angular Momentum
$L = I \cdot \omega$

$L = 4.5 \cdot 3 = 13.5 \text{ } K g \cdot {m}^{2} / \sec$

God bless....I hope the explanation is useful.