A cylinder has inner and outer radii of $2 c m$ $2 cm$ and $4 c m$ $4 cm$ , respectively, and a mass of $15 k g$ $15 kg$ . If the cylinder's frequency of counterclockwise rotation about its center changes from $4 H z$ $4 Hz$ to $7 H z$ $7 Hz$ , by how much does its angular momentum change?

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Answer 1 · 2017-02-01T14:39:37

The answer is $= 0.283 k g m s^{- 1}$ $=0.283kgms^(-1)$

The angular momentum is $L = I ω$ $L=Iomega$

where $I$ $I$ is the moment of inertia

$DeltaL=IDelta omega$

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

So, $I=15*(0.02^2+0.04^2)/2=0.015kgm^2$

$Delta omega=(7-4)*2pi=6pi rads^-1$

$DeltaL=0.015*6pi=0.283kgms^(-1)$

A cylinder has inner and outer radii of 2 cm2cm2 cm and 4 cm4cm4 cm, respectively, and a mass of 15 kg15kg15 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 4 Hz4Hz4 Hz to 7 Hz7Hz7 Hz, by how much does its angular momentum change?