A cylinder has inner and outer radii of #16 cm# and #21 cm#, respectively, and a mass of #3 kg#. If the cylinder's frequency of rotation about its center changes from #4 Hz# to #9 Hz#, by how much does its angular momentum change?

1 Answer
Apr 7, 2017

Answer:

The change in angular momentum is #=3.28kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

Mass, #m=3kg#

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

So, #I=3*((0.16^2+0.21^2))/2=0.105kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(9-4)*2pi=(10pi)rads^-1#

The change in angular momentum is

#DeltaL=0.105*10pi=3.28kgm^2s^-1#