A cylinder has inner and outer radii of #4 cm# and #8 cm#, respectively, and a mass of #3 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #12 Hz# to #7 Hz#, by how much does its angular momentum change?

1 Answer
Mar 8, 2017

Answer:

The change in angular momentum is #=0.38kgm^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=3*(0.04^2+0.08^2)/2=0.012kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(12-7)*2pi=10pirads^-1#

The change in angular momentum is

#DeltaL=0.012*10pi=0.38kgm^2s^-1#