A cylinder has inner and outer radii of #9 cm# and #11 cm#, respectively, and a mass of #5 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
Jul 18, 2018

Answer:

The change in angular momentum is #=0.635kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

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

The mass of the cylinder is #m=5 kg#

The radii are #r_1=0.09m# and #r_2=0.11m#

So, the moment of inertia is

#I=5*(0.09^2+0.11^2)/2=0.0505kgm^2#

The change in angular velocity is

#Deltaomega=2pi(7-5)=4pirads^-1#

The change in angular momentum is

#DeltaL=IDeltaomega=0.0505*4pi=0.635kgm^2s^-1#