Question

Along a streamline

• A. the velocity of a fluid particle remains constant.
• B. the velocity of all fluid particles at a given instant is constant.
• C. the speed of a fluid particle remains constant.
• D. the velocity of all fluid particles crossing a given position is constant.

Answer 1

The correct option is D the velocity of all fluid particles crossing a given position is constant.

For a streamline flow of a liquid, flow rate
$Av=$ constant (law of continuity)
between two cross-section of a tube of flow.
This means that at a particular cross-section, the velocity of all fluid particles is constant.
Hence, we can say that the velocity of all fluid particles crossing a given position is constant.

Final Answer: $\left(B\right)$