Calculate the center of mass of the homogenous surface $\displaystyle z = \sqrt{x^2 + y^2}$ between the planes z= 1 and z = 2
I solved, thanks anyway.
$\displaystyle \overline{x}$ = 0 (because the cone is symmetric to the plane YZ)
$\displaystyle \overline{y}$ = 0 (because the cone is symmetric to the plane XZ)
$\displaystyle \overline{z}$ = 14/9 (Using the definition)
--> I hadn't realized that using symmetry I could solve almost the whole problem.