A cylinder has inner and outer radii of #5 cm# and #9 cm#, respectively, and a mass of #8 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #15 Hz# to #7 Hz#, by how much does its angular momentum change?

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Answer 1 · 2017-01-21T14:11:39

The answer is #=2.131kgms^-1#

The angular momentum is #L=Iomega#

For a cylinder, #I=(m(r_1^2+r_2^2))/2#

So, #I=8*(((0.09)^2+(0.05)^2))/2=4*0.0106=0.0424kgm^2#

#L_1=0.0424*15*2pi=3.996kgms^(-1)#

#L_2=0.0424*7*2pi=1.865kgms^-1#

#DeltaL=L_1-L_2=3.996-1.865=2.131kgms^-1#