Water flows through a constriction in horizontal pipe as it enters the constriction, the water's:
Correct answer: C. Speed increases and pressure decreases
- A. Speed increases and pressure remains constant
- B. Speed increases and pressure increase
- C. Speed increases and pressure decreases
- D. Speed decreases and pressure Increases
Explanation
We know that the volume flow rate (Avt) is constant, with V/v = A, we know that Area is directionally proportional to velocity. 'Constriction' tells us that the area has decreased, thus the speed increases.According to Bernolie's theorem P + pgh + 1/2 = constant.Value for pgh is constant as it depends on height, the value for 1/2pv2 increases as velocity increases, thus to maintain the constant the value of pressure must decrease.
This question appeared on the ETEA MDCAT 2015 paper, which you can sit online with every answer explained.
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About Bernoulli's Equation
Bernoulli’s equation applies conservation of energy to steady flow of an incompressible, non-viscous fluid along a streamline: pressure, kinetic and gravitational terms have a constant total. It explains pressure-speed changes in narrow pipes, Venturi meters and lift, and differs from continuity because it relates pressure as well as velocity and height.
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