# A solid disk, spinning counter-clockwise, has a mass of 4 kg and a radius of 3/7 m. If a point on the edge of the disk is moving at 5/9 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

Jun 15, 2016

#### Answer:

$L = I w = M {R}^{2} \cdot \frac{v}{R} = \left(4\right) {\left(\frac{3}{7}\right)}^{2} \cdot \frac{\frac{5}{9}}{\frac{3}{7}} = 0.950$

#### Explanation:

Like linear momentum;
p = mv.

Angular momentum equals the angular component of mass multiplied by the angular velocity,
hence;
L (angular momentum) = I (inertia) x w (angular velocity).

Inertia of a solid disk = $M {R}^{2}$, where R = radius, and M = mass of disk.

Angular velocity equals tangential velocity divided by radius.