A cylinder has inner and outer radii of #5 cm# and #9 cm#, respectively, and a mass of #5 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #15 Hz# to #7 Hz#, by how much does its angular momentum change?

1 Answer
Jun 6, 2017

Answer:

The change in angular momentum is #=1.33kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

Mass, #m=5kg#

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

So, #I=5*((0.05^2+0.09^2))/2=0.0265kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(15-7)*2pi=(16pi)rads^-1#

The change in angular momentum is

#DeltaL=0.0265*16pi=1.33kgm^2s^-1#