A cylinder has inner and outer radii of $9 c m$ $9 cm$ and $11 c m$ $11 cm$ , respectively, and a mass of $9 k g$ $9 kg$ . If the cylinder's frequency of counterclockwise rotation about its center changes from $5 H z$ $5 Hz$ to $7 H z$ $7 Hz$ , by how much does its angular momentum change?

Question

1419 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-04-04T11:33:50

The change in angular momentum is $= 1.14 k g m^{2} s^{- 1}$ $=1.14kgm^2s^-1$

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

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

Mass, $m = 9 k g$ $m=9kg$

For a cylinder, $I = m \frac{(r_{1}^{2} + r_{2}^{2})}{2}$ $I=m((r_1^2+r_2^2))/2$

So, $I = 9 \cdot \frac{({0.09}^{2} + {0.11}^{2})}{2} = 0.091 k g m^{2}$ $I=9*((0.09^2+0.11^2))/2=0.091kgm^2$

The change in angular momentum is

$DeltaL=IDelta omega$

The change in angular velocity is

$Delta omega=(7-5)*2pi=(4pi)rads^-1$

The change in angular momentum is

$DeltaL=0.091*4pi=1.14kgm^2s^-1$

A cylinder has inner and outer radii of 9 cm9cm9 cm and 11 cm11cm11 cm, respectively, and a mass of 9 kg9kg9 kg. If the cylinder's frequency of counterclockwise rotation about its center changes from 5 Hz5Hz5 Hz to 7 Hz7Hz7 Hz, by how much does its angular momentum change?