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The differential mass element $dmass$ is derived by multiplying the local density $\rho(x,y,z)$ by the infinitesimal volume element $dV$. For the example density $\rho(x,y,z)=xyz$, this gives $dmass = xyz \, dV$.

Conditions: The object has non-uniform density.; The density is modeled as a function of position $(x,y,z)$.; $dV$ denotes an infinitesimal volume element.

The differential mass element $dmass$ is derived by multiplying the local density $\rho(x,y,z)$ by the infinitesimal volume element $dV$. For the example density $\rho(x,y,z)=xyz$, this gives $dmass = xyz \, dV$.

Conditions: The object has non-uniform density.; The density is modeled as a function of position $(x,y,z)$.; $dV$ denotes an infinitesimal volume element.