A cylinder has inner and outer radii of #4 cm# and #8 cm#, respectively, and a mass of #3 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #2 Hz# to #7 Hz#, by how much does its angular momentum change?

1 Answer
Jun 23, 2017

Answer:

The angular momentum changes by #=0.38kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

The mass, #m=3kg#

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

So, #I=3*((0.04^2+0.08^2))/2=0.012kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(7-2)*2pi=(10pi)rads^-1#

The change in angular momentum is

#DeltaL=0.012*10pi=0.38kgm^2s^-1#