A viscous liquid is flowing through a cylindrical pipe. The velocity distribution of fluid is best represented by the diagram,

Assertion: A stream of water flowing at high speed from a garden hose-pipe tends to spread like a fountain when held vertically up but tends to narrow down when held vertically down.

Reason: In any steady flow of an incompressible fluid, the volume flow rate of the fluid remains constant.

When a body falls in air, the resistance of air depends to a great extent on the shape of the body. Three different shapes are given. Identify the combination of air resistances which truly represent the physical situation. (The cross-sectional areas are the same.)

An ideal fluid flows through a pipe of circular cross-section with diameters $5 \mathrm{cm}$ and $10 \mathrm{cm}$ as shown. The ratio of velocities of fluid at $A$ and $B$ is,