A cylinder has inner and outer radii of #4 cm# and #9 cm#, respectively, and a mass of #7 kg#. If the cylinder's frequency of counterclockwise rotation about its center changes from #7 Hz# to #8 Hz#, by how much does its angular momentum change?

1 Answer
Feb 19, 2017

Answer:

The change in angular momentum is #=0.21kgm^2s^-1#

Explanation:

The angular momentum is #L=Iomega#

where #I# is the moment of inertia

and #omega# is the angular velocity

The change in angular momentum is

#Delta L=I Delta omega#

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

So, #I=7*(0.04^2+0.09^2)/2=0.03395kgm^2#

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

#Delta L=0.03395*2pi=0.21kgm^2s^-1#