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

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Answer 1 · 2017-08-05T20:06:05

The angular momentum is $= 2.4 k g m^{2} s^{- 1}$ $=2.4kgm^2s^-1$
The angular velocity is $= 0.13 r a d s^{- 1}$ $=0.13rads^-1$

The angular velocity is

$omega=(Deltatheta)/(Deltat)$

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

$omega=v/r$

where,

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

$r=3m$

So,

The angular velocity is $omega=(2/5)/(3)=0.13rads^-1$

The angular momentum is $L=Iomega$

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

So, $I=4*(3)^2/2=18kkgm^2$

The angular momentum is

$L=0.13*18=2.4kgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 4 kg4kg4 kg and a radius of 3 m3m3 m. If a point on the edge of the disk is moving at 2/5 m/s25ms2/5 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?