A vertical rectangular gate is $8 \mathrm{ft}$ wide and $10 \mathrm{ft}$ long and weighs 6000 lb. The gate slides in vertical slots in the side of a reservoir containing water. The coefficient of friction between the slots and the gate is $0.03 .$ Determine the minimum vertical force required to lift the gate when the water level is $4 \mathrm{ft}$ above the top edge of the gate.