A solid disk, spinning counter-clockwise, has a mass of #7 kg# and a radius of #5 m#. If a point on the edge of the disk is moving at #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

#omega=0.4color(white)is^-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#