A triangular shaped gate is hinged at point $A,$ as shown. Knowing that the weight of the gate is $600\frac{N}{m},$ determine the force

needed to keep the gate at its position per unit width. The line of action of the weight of the gate is denoted by the dashed line.

Take the density of water to be $1000k\frac{g}{m^3}.$ The height $h$ of the gate is $2$ m $.$ In the given figure the thickness of the gate is not

considered. The force needed to keep the gate at its position per unit width is $18,919\frac{N}{m}.$ Find length $g[m]$ :