A water hose of internal diameter 20 mm at the outlet discharges 30 kg of water in 60s. What will be the water speed at the outlet? (Flow is steady and density of water is 1000 kg/m³)
Correct answer: D. 1.592 m/s
- A. 25.6 m/s
- B. 3.45 m/s
- C. 1.23 m/s
- D. 1.592 m/s
Explanation
Correct calculation: mass flow = 30 kg/60 s = 0.5 kg/s ⇒ volumetric Q = 0.5/1000 = 5×10⁻⁴ m³/s. Area A = π(0.01)² ≈ 3.14×10⁻⁴ m² ⇒ v = Q/A ≈ 0.0005/0.000314 ≈ 1.592 m/s.
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