Calculating Rotational Inertia for a Section of a Right Circular Cylinder

[brad sue]

Hi,
Please take a look at this:

Calculate the rotational inertia of a section of a right circular cylinder of radius R that subtends an angle of 'theta knot' at the origin when the reference axis is at the origin and perpendicular to the section.

I tried to draw the picture in the attachment.
I tried to use the formula I=Integral(R²*dm), with dm =density*dV
where V is the volume. I would like to know if I am in the good direction

Thank you for your help

B

 

[Galileo]

Calculate the rotational inertia of a section of a right circular cylinder of radius R that subtends an angle of 'theta knot' at the origin when the reference axis is at the origin and perpendicular to the section.

Lol, isn't it 'theta naught'? As in $\theta_0$?

$$I=\int_V R^2\rho dV$$
is always correct. You should go to cilindrical coordinates for this problem.

 

[brad sue]

Help

Hi I am still stuck with with problem of inertia . please can someone help me.
Can you give me more suggestions
Brad

 

[Euclid]

If I understand the question correctly, maybe this will help
$$\int_V R^2\rho dV =\rho \int_V r^2 r dr d\phi dz$$