Practice question · Multiple choice
You partly block a garden hose with your thumb and the water jets out faster. What made the water speed up?
Hints
- What flows in per second must flow out per second: .
- Half the exit area → twice the exit speed. Pressure at a free jet’s opening is just atmospheric.
Show the answer
B. The same flow must squeeze through a smaller area, continuity demands more speed
Why
Continuity (mass conservation) forces : shrink the opening and the speed rises to carry the same flow. Rivers do it too, the same water that dawdles through wide pools races through narrow gorges.
Practise Fluid Dynamics: Continuity and Bernoulli's Equation
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