An electric lift with a maximum load of $2000 \mathrm{kg}$ (lift $+$ passengers) is moving up with a constant speed of $1.5{ \mathrm{m} \mathrm{s}}^{-1}$. The frictional force opposing the motion is $3000 \mathrm{N}$. The minimum power delivered by the motor to the lift in watts is : $\left(g=10{ \mathrm{m} \mathrm{s}}^{-2}\right)$