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

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Answer 1 · 2017-10-29T06:58:47

$ω = 0.4 i s^{- 1}$ $omega=0.4color(white)is^-1$
$L = 7 i k g m^{2} s^{- 1}$ $L=7color(white)ikgm^2s^-1$

Angular Velocity:

$omega=(Deltatheta)/(Deltat)$

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

So, $omega=v/r$

Here,

$v=2m/s$

$r=5m/$

$thereforeomega=(2m/s)/(5m)=0.4color(white)is^-1$

$L=Iomega$

Here,

$I("moment of inertia")=(mr^2)/2$
$=(7kg*(5m)^2)/2=17.5color(white)ikgm^2$

$omega=0.4color(white)i"rads"^-1$

$thereforeL=17.5color(white)ikgm^2*0.4color(white)i"rads"^-1$
$=7color(white)ikgm^2s^-1$

A solid disk, spinning counter-clockwise, has a mass of 7 kg7kg7 kg and a radius of 5 m5m5 m. If a point on the edge of the disk is moving at 2 m/s2ms2 m/s in the direction perpendicular to the disk's radius, what is the disk's angular momentum and velocity?