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

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Answer 1 · 2017-05-05T06:05:29

The angular momentum is $= 20 k g m^{2} s^{- 1}$ $=20kgm^2s^-1$
The angular velocity is $= 0.5 r a d s - 1$ $=0.5rads-1$

The angular velocity is

$omega=(Deltatheta)/(Deltat)$

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

$omega=v/r$

where,

$v=2ms^(-1)$

$r=4m$

So,

$omega=(2)/(4)=0.5rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=5*(4)^2/2=40kgm^2$

The angular momentum is

$L=40*0.5=20kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 5 kg5kg5 kg and a radius of 4 m4m4 m. If a point on the edge of the disk is moving at a rate of 2 m/s2ms2 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?