If the maximum load carried by an elevator is $1400 \mathrm{kg}$ $(600 \mathrm{kg}\text{-Passengers} +800 \mathrm{kg}\text{-elevator})$ , which is moving up with a uniform speed of $3 \mathrm{m} {\mathrm{s}}^{-1}$ and the frictional force acting on it is $2000 \mathrm{N}$, then the maximum power used by the motor is _____________$\mathrm{kW}. \left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$