Euler's equations (rigid body dynamics)
= Euler's equations
{disambiguate=rigid body dynamics}
{c}
{title2=$I\dot\omega+\omega\times(I\omega)=\tau$}
{wiki}
In principal body coordinates, <Euler's equations (rigid body dynamics)> express <angular momentum> balance as $I\dot\omega+\omega\times(I\omega)=\tau$, with applied <torque> $\tau$. Setting the torque to zero gives the following torque-free specialization.