Rotational Inertia of Solid Disk

[Kickbladesama]

Homework Statement

What is the rotational inertia of a solid iron disk of mass 46 kg, with a thickness of 6.31 cm and radius of 19.4 cm, about an axis through its center and perpendicular to it?

Homework Equations

either 1/2MR^(2) or I = sigma (1->N) Mi x Ri^(2)

The Attempt at a Solution

I don't know what to do!

 

[tiny-tim]

Welcome to PF!

What is the rotational inertia of a solid iron disk of mass 46 kg, with a thickness of 6.31 cm and radius of 19.4 cm, about an axis through its center and perpendicular to it?

Hi Kickbladesama! Welcome to PF!

Hint: divide the disc into concentric slices of thickness dr, and integrate.