Moment of Inertia Converter — kg·m², lb·ft², g·cm²
Convert between 6 units of moment of inertia — kg·m², kg·cm², g·cm², lb·ft², lb·in², and oz·in². Moment of inertia measures resistance to rotational acceleration (I = mr²). A hollow cylinder is harder to spin than a solid one of the same mass. Used in electric motor sizing, flywheel energy storage, robotic joint design and vehicle dynamics.
About the Moment of Inertia Converter
Moment of inertia (also called rotational inertia) measures how difficult it is to change the rotational speed of an object — the rotational equivalent of mass in linear motion. It depends on both the mass and how that mass is distributed relative to the rotation axis. The SI unit is kg·m². Engineers use it in flywheel design, motor selection, gear systems, and any application involving rotating machinery.
- ›A solid cylinder's moment of inertia = ½mr² — hollow cylinders are harder to spin for the same mass
- ›Figure skaters pull in their arms to reduce moment of inertia and spin faster (conservation of angular momentum)
- ›Flywheels in energy storage systems are designed with high moment of inertia to store more rotational energy
- ›Moment of inertia × angular acceleration = torque (the rotational analogue of F = ma)