A cylinder has inner and outer radii of #3 cm# and #9 cm#, respectively, and a mass of #4 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #7 Hz# to #6 Hz#, by how much does its angular momentum change?

1 Answer
Jun 16, 2017

The angular momentum changes by #=0.11kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

Mass, #m=4kg#

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

So, #I=4*((0.03^2+0.09^2))/2=0.018kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(7-6)*2pi=(2pi)rads^-1#

The change in angular momentum is

#DeltaL=0.018*2pi=0.11kgm^2s^-1#