
The problem involves Bernoulli's equation, which states: P1 + (1/2)ρv12 + ρgh = P2 + (1/2)ρv22. Given data: ρ = 800 kg/m3, P1 - P2 = 4100 Pa, h = 1 m, g = 10 m/s2, A1 = a, A2 = a/2.
By the equation of continuity: A1v1 = A2v2, so v2 = 2v1.
Substitute in Bernoulli's equation: 4100 = (1/2)(800)(4v12 - v12) - 800(10)(1).
This simplifies to: 4100 + 8000 = 1200v12.
Simplifying further: 12100 = 1200v12.
Thus, v12 = 10.08, so v1 = √10.08.
Given v1 = √x/6, equate and find x: √x/6 = √10.08.
Therefore, x = 10.08 × 36 = 363.
Verify: 363 is within the given range (363,363).
A square gate of size 1m × 1m is hinged at its mid-point. A fluid of density ρ fills the space to the left of the gate. The force F required to hold the gate stationary is 
A square gate of size \(1\,\text{m} \times 1\,\text{m}\) is hinged at its mid-point. A fluid of density \(\rho\) fills the space to the left of the gate. The force \(F\) required to hold the gate stationary is: 