Answer:
Since the weight cannot take a negative value, it is concluded that the minimum weight required for the gate is zero, because the same pressure force will rotate the gate.
Step-by-step explanation:
Given:
L = 12 m
F = 60 kN
w = 4 m
H = 9 m
The pressure force is:

The center of pressure is:

If the moment is equal to zero,
