= Constant-power rotation against dry friction
{title2=$I\dot\omega=P/\omega-\tau_f$}
For positive <angular velocity>, a motor delivering constant mechanical <power> $P$ produces <torque> $P/\omega$. With constant opposing <kinetic friction> torque $\tau_f$, <angular momentum> balance gives the displayed equation and a steady speed $\omega_*=P/\tau_f$. A small increase in speed reduces the driving torque below the friction torque, making this equilibrium stable within the model. The constant-power idealization is singular at exact rest and requires a separate starting regime in a real motor.
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