Practice question
Question
Water flows at 2.9m/s at 3.2m height with pressure 1.9×105Pa. What is the pressure at 1.8m height with speed 4.0m/s? (ρ\=1000kg/m3, g\=10m/s2)
Explanation
Bernoulli’s: P1+12ρv12+ρgh1 = P2+12ρv22+ρgh2. Left: 1.9×105+12×1000×8.41+1000×10×3.2 = 1.9×105+4205+32000 = 2.26205×105. Right: P2+12×1000×16+1000×10×1.8 = P2+8000+18000 = P2+26000. 2.26205×105 = P2+26000, P2 = 2.00205×105Pa. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.00 × 10⁵ Pa. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.