A solid disk, spinning counter-clockwise, has a mass of $4 k g$ $4 kg$ and a radius of $7 m$ $7 m$ . If a point on the edge of the disk is moving at $12 \frac{m}{s}$ $12 m/s$ in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?

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Answer 1 · 2017-10-25T06:02:07

The angular momentum is $= 168 k g m^{2} s^{- 1}$ $=168kgm^2s^-1$ and the angular velocity is $= \frac{12}{7} r a d s^{- 1}$ $=12/7rads^-1$

The angular velocity is

$omega=(Deltatheta)/(Deltat)$

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

$omega=v/r$

where,

$v=12ms^(-1)$

$r=7m$

So,

$omega=(12)/(7)=12/7rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=4*(7)^2/2=98kgm^2$

The angular momentum is

$L=98*12/7=168kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 4 kg4kg4 kg and a radius of 7 m7m7 m. If a point on the edge of the disk is moving at 12 m/s12ms12 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?