A gate having the cross section shown in Fig. P2.103 is \(4 \mathrm{ft}\) wide and is hinged at \(C\). The gate weighs \(18,000 \mathrm{lb}\), and its mass center is \(1.67 \mathrm{ft}\) to the right of the plane \(B C\). Determine the vertical reaction at \(A\) on the gate when the water level is \(3 \mathrm{ft}\) above the base. All contact surfaces are smooth.

Figure P2.103

9 ft 3 ft Water surface, B 5 ft- Hinge