A cylinder has inner and outer radii of #9 cm# and #12 cm#, respectively, and a mass of #7 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #24 Hz# to #18 Hz#, by how much does its angular momentum change?

1 Answer
Jul 10, 2017

Answer:

The change in angular momentum is #=2.97kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

The mass, #m=7kg#

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

So, #I=7*((0.09^2+0.12^2))/2=0.07875kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(24-18)*2pi=(12pi)rads^-1#

The change in angular momentum is

#DeltaL=0.07875*12pi=2.97kgm^2s^-1#