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?

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Answer 1 · 2017-02-19T06:17:58

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

The angular momentum is $L=Iomega$

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

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

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

A cylinder has inner and outer radii of 4 cm4 cm and 9 cm9 cm, respectively, and a mass of 7 kg7 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 7 Hz7 Hz to 8 Hz8 Hz, by how much does its angular momentum change?