A cylinder has inner and outer radii of #12 cm# and #15 cm#, respectively, and a mass of #6 kg#. If the cylinder's frequency of rotation about its center changes from #7 Hz# to #3 Hz#, by how much does its angular momentum change?

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Answer 1 · 2017-03-17T14:48:46

The angular momentum changes by #0.93kgm^2s^-1#

The angular momentum is #L=Iomega#

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

So, #I=6*((0.12^2+0.15^2))/2=0.0369kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(7-3)*2pi=(8pi)rads^-1#

The change in angular momentum is

#DeltaL=0.0369*8pi=0.93kgm^2s^-1#