A cylinder has inner and outer radii of #9 cm# and #16 cm#, respectively, and a mass of #4 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #9 Hz# to #4 Hz#, by how much does its angular momentum change?

1 Answer
Mar 7, 2017

Answer:

The change in angular momentum is #=2.12kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

So, #I=4*(0.09^2+0.16^2)/2=0.0674kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(9-4)*2pi=10pirads^-1#

The change in angular momentum is

#DeltaL=0.0674*10pi=2.12kgm^2s^-1#