Planar lamina:

A thin flat plate of material of constant density is called a planar lamina.

Moments and center of mass of a planar lamina:

Let and  be continuous functions such that on , and consider the planar lamina of uniform density  bounded by the graphs of and .

The moments about the -and -axis are

.

.

The center of mass is and , where is the mass of the lamina.

A thin flat plate of material of constant density is called a planar lamina.

The moments about the -and -axis are

.

.

The center of mass is and , where is the mass of the lamina.