A solid disk, spinning counter-clockwise, has a mass of $3 kg$ and a radius of $8/5 m$ . If a point on the edge of the disk is moving at $7/4 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2017-02-27T12:53:03

The angular momentum is $=31.6kgm^2s^-1$
The angular velocity is $=6.87rads^-1$

The angular velocity is

$omega=v/r$

where,

$v=7/4ms^(-1)$

$r=8/5m$

So,

$omega=(7/4)/(8/5)*2pi=6.87rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=3*(7/4)^2/2=147/32kgm^2$

$L=6.87*147/32=31.6kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 3 kg3 kg and a radius of 8/5 m8/5 m. If a point on the edge of the disk is moving at 7/4 m/s7/4 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?