μm⁴

micrometer to the fourth

Area moment of inertiaexact by definition

The micrometre to the fourth is 10⁻²⁴ m⁴, exact by prefix. It is the working unit of microelectromechanical design, where a silicon cantilever a few micrometres thick has a second moment of area of a handful of μm⁴ and that number sets its stiffness and resonant frequency.

1 μm⁴ 1.0000000e-12 mm⁴