Water falls from a tap, down the streamline
Correct answer: A. Area decreases
- A. Area decreases
- B. Area increases
- C. Velocity remains same
- D. Area remains same
Explanation
The correct answer is that the area decreases. As the water falls from the tap, it accelerates under gravity, increasing its velocity. According to the principle of continuity, which states that the product of cross-sectional area and velocity remains constant for an incompressible fluid, the cross-sectional area of the stream must decrease as velocity increases. This is why the stream of water narrows as it falls. The other options are incorrect because they do not account for the effect of gravity on the falling water and the principles governing fluid flow.
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About Fluid Dynamics
Fluid flow is described through speed, pressure and density, including steady flow and the equation of continuity for conserving mass. Bernoulli's equation relates pressure, speed and height, while fluid drag and terminal velocity explain why a falling object eventually moves at constant speed when drag balances its weight.
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