Question

A square gate, 1.5 m $\times$1.5 m, one of the vertical sides of a fully filled water tank, has one side on the free water surface. It is hinged on the lower horizontal side and is held in position by a force applied on the vertical central line at a depth of 0.75 m below the free surface. The right magnitude of this force is

• A. 500 $\times$9.81 N
• B. 600 $\times$9.81 N
• C. 750 $\times$9.81 N
• D. 1125 $\times$9.81 N

Answer 1

The correct option is D 1125 $\times$9.81 N


$\left(\rho gA\overline{h}\right)0.5=F\times 0.751000\times 9.81\times (1.5\times 1.5)\times 0.75\times 0.5=F\times 0.75F=1125\times 9.81N$