A solid disk, spinning counter-clockwise, has a mass of $14 kg$ and a radius of $3/4 m$ . If a point on the edge of the disk is moving at $7/9 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2017-02-23T16:07:43

The angular momentum is $=25.7kgm^2s^-1$
The angular velocity is $=6.52rads^-1$

The angular velocity is

$omega=v/r$

where,

$v=7/9ms^(-1)$

$r=3/4m$

So,

$omega=(7/9)/(3/4)*2pi=56/27pi=6.52rads^-1$

The angular momentum is $L=Iomega$

For a solid disc, $I=(mr^2)/2$

So, $I=14*(3/4)^2/2=63/16=63/16kgm^2$

$L=6.52*63/16=25.7kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 14 kg14 kg and a radius of 3/4 m3/4 m. If a point on the edge of the disk is moving at 7/9 m/s7/9 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?