A solid disk, spinning counter-clockwise, has a mass of $4 kg$ and a radius of $3/7 m$ . If a point on the edge of the disk is moving at $5/2 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2017-08-09T06:11:41

The angular momentum is $=2.14kgm^2s^-1$ and the angular velocity is $=5.83rads^-1$

The angular velocity is

$omega=(Deltatheta)/(Deltat)$

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

$omega=v/r$

where,

$v=5/2ms^(-1)$

$r=3/7m$

So,

$omega=(5/2)/(3/7)=35/6=5.83rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=4*(3/7)^2/2=18/49kgm^2$

The angular momentum is

$L=18/49*35/6=2.14kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 4 kg4 kg and a radius of 3/7 m3/7 m. If a point on the edge of the disk is moving at 5/2 m/s5/2 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?