Water coming out of the mouth of a tap and falling vertically in stream line flwo forms a tapering column. i.e., the area of cross-section of the liquid column decreases as it moves down which of the following is the most accurate explanantion for this-
A. As the moves down, its speed increases and hence its pressure decreases. It is then compressed by the atmosphere.
B. Falling water tries to to reach a terminal velocity and hence reduced the area of cross-section to balance upward and downward force.
C. The mass of water flowing past and cross-section must remain constant. Also, water is almost incompressible. Hence the rate of volume flow must remain constant. As this is equal to velocity x area, the area decreases as velocity increases.
D. The surface tension causes the exposed surface area of the liquid to decrease continuously.
