A cylinder has inner and outer radii of #8 cm# and #15 cm#, respectively, and a mass of #3 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #14 Hz# to #12 Hz#, by how much does its angular momentum change?

1 Answer
Aug 12, 2017

Answer:

The change in angular momentum is #=0.54kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

The mass of the cylinder is #m=3kg#

The radii of the cylinder are #r_1=0.08m# and #r_2=0.15m#

For the cylinder, the moment of inertia is #I=m(r_1^2+r_2^2)/2#

So, #I=3*(0.08^2+0.15^2)/2=0.04335kgm^2#

The change in angular velocity is

#Delta omega=Deltaf*2pi=(14-12)*2pi=4pirads^-1#

The change in angular momentum is

#DeltaL=I Delta omega=0.04335*4pi=0.54kgm^2s^-1#