A cylinder has inner and outer radii of #9 cm# and #11 cm#, respectively, and a mass of #9 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #5 Hz# to #7 Hz#, by how much does its angular momentum change?

1 Answer
Apr 4, 2017

Answer:

The change in angular momentum is #=1.14kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

Mass, #m=9kg#

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

So, #I=9*((0.09^2+0.11^2))/2=0.091kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(7-5)*2pi=(4pi)rads^-1#

The change in angular momentum is

#DeltaL=0.091*4pi=1.14kgm^2s^-1#