A solid disk, spinning counter-clockwise, has a mass of $4 kg$ and a radius of $7 m$ . If a point on the edge of the disk is moving at $8 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2016-10-30T11:03:14

The angular momentum is $=112 kgm^2/s$
The angular velocity is $=8/7 Hz$

Let's start by calculating the angular velocity
we use the equation
$v=8 m/s$
$r=7m$

$v=r*omega$
and $omega=v/r=8/7 Hz$

The moment of inertia of the solid disc $I=m*r^2/2$
So $I=4*7*7/2=98 kgm^2$
Then the angular momentum is $L=Iomega$
so, $L=98*8/7=112kgm^2/s$

A solid disk, spinning counter-clockwise, has a mass of 4 kg4 kg and a radius of 7 m7 m. If a point on the edge of the disk is moving at 8 m/s8 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?