A cylinder has inner and outer radii of $5 cm$ and $11 cm$ , respectively, and a mass of $5 kg$ . If the cylinder's frequency of counterclockwise rotation about its center changes from $15 Hz$ to $6 Hz$ , by how much does its angular momentum change?

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Answer 1 · 2017-12-23T06:50:42

The change in angular momentum is $=2.064kgm^2s^-1$

The angular momentum is $L=Iomega$

and $omega$ is the angular velocity

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

The radii of the cylinder are $r_1=0.05m$ and $r_2=0.11m$

For the cylinder, the moment of inertia is $I=m((r_1^2+r_2^2))/2$

So, $I=5*((0.05^2+0.11^2))/2=0.0365kgm^2$

The change in angular velocity is

$Delta omega=Deltaf*2pi=(15-6) xx2pi=18pirads^-1$

The change in angular momentum is

$DeltaL=IDelta omega=0.0365 xx18pi=2.064kgm^2s^-1$

A cylinder has inner and outer radii of 5 cm5 cm and 11 cm11 cm, respectively, and a mass of 5 kg5 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 15 Hz15 Hz to 6 Hz6 Hz, by how much does its angular momentum change?