A solid disk, spinning counter-clockwise, has a mass of $12 kg$ and a radius of $3/8 m$ . If a point on the edge of the disk is moving at $7/5 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2017-07-03T05:07:41

The angular momentum is $=3.15kgm^2s^-1$ and the angular velocity is $=3.73rads^-1$

The angular velocity is

$omega=(Deltatheta)/(Deltat)$

$v=r*((Deltatheta)/(Deltat))=r omega$

$omega=v/r$

where,

$v=7/5ms^(-1)$

$r=3/8m$

So,

$omega=(7/5)/(3/8)=56/15=3.73rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=12*(3/8)^2/2=0.84kgm^2$

The angular momentum is

$L=0.84*3.73=3.15kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 12 kg12 kg and a radius of 3/8 m3/8 m. If a point on the edge of the disk is moving at 7/5 m/s7/5 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?