Planar lamina

In mathematics, a planar lamina is a closed set in a plane of mass ${\displaystyle m}$ and surface density ${\displaystyle \rho \ (x,y)}$ such that:

The center of mass of the lamina is at the point

where ${\displaystyle M_{y}}$ moment of the entire lamina about the x-axis and ${\displaystyle M_{x}}$ moment of the entire lamina about the y-axis.

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