A cylinder has inner and outer radii of #2 cm# and #6 cm#, respectively, and a mass of #1 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #10 Hz# to #15 Hz#, by how much does its angular momentum change?

1 Answer
Sep 6, 2017

Answer:

The change in angular momentum is #=0.13kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

The mass of the cylinder is #m=1kg#

The radii of the cylinder are #r_1=0.02m# and #r_2=0.06m#

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

So, #I=1*(0.02^2+0.06^2)/2=0.004kgm^2#

The change in angular velocity is

#Delta omega=Deltaf*2pi=(15-10)*2pi=10pirads^-1#

The change in angular momentum is

#DeltaL=I Delta omega=0.004*10pi=0.13kgm^2s^-1#