A cylinder has inner and outer radii of #8 cm# and #15 cm#, respectively, and a mass of #1 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #15 Hz# to #12 Hz#, by how much does its angular momentum change?

1 Answer
Jul 4, 2018

Answer:

The change in angular momentum is #=0.27kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

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

The radii are #r_1=0.08m# and #r_2=0.15m#

So, the moment of inertia is

#I=1*(0.08^2+0.15^2)/2=0.01445kgm^2#

The change in angular velocity is

#Deltaomega=2pi(15-12)=6pirads^-1#

The change in angular momentum is

#DeltaL=IDeltaomega=0.01445*6pi=0.27kgm^2s^-1#