The size $HB$ rectangular and vertical gate on a water tank seen on the drawing is considered. The gate is hinged at its top point and balanced with a wight $W$ acting $L$ distance away from the hinge.

What should the value of the weight $W^{**}$ be if it is required that the gate should start to open when the water height reach to $h^{**}.$

A stop prevents the gate to move clockwise.

$h^{**}=3,5[m]$

$H=4,5[m]$

$L=1,5[m]$

$B=2,0[m]$