A cylinder has inner and outer radii of #8 cm# and #15 cm#, respectively, and a mass of #6 kg#. If the cylinder's frequency of rotation about its center changes from #7 Hz# to #3 Hz#, by how much does its angular momentum change?

1 Answer
May 2, 2017

Answer:

The change in angular momentum is #=2.18kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

Mass, #m=6kg#

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

So, #I=6*((0.08^2+0.15^2))/2=0.0867kgm^2#

The change in angular momentum is

#DeltaL=IDelta omega#

The change in angular velocity is

#Delta omega=(7-3)*2pi=(8pi)rads^-1#

The change in angular momentum is

#DeltaL=0.0867*8pi=2.18kgm^2s^-1#