A solid disk, spinning counter-clockwise, has a mass of $13 kg$ and a radius of $4/5 m$ . 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 · 2017-02-11T17:17:56

The angular momentum is $=57kgms^(-1)$
The angular veocity is $=13.7rads^-1$

The angular velocity is

$omega=v/r$

where,

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

$r=4/5m$

So,

$omega=(7/4)/(4/5)*2pi=70/16pi=13.7 rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=13*(4/5)^2/2=208/50=4.16kgm^2$

$L=13.7*4.16=57kgms^(-1)$

A solid disk, spinning counter-clockwise, has a mass of 13 kg13 kg and a radius of 4/5 m4/5 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?