Practice question
Question
A pipe has a cross-sectional area of 0.02m2 at one end and 0.01m2 at the other. If water flows at 2m/s through the wider end, what is the speed at the narrower end?
Explanation
Using the equation of continuity: A1v1 = A2v2. A1 = 0.02m2, v1 = 2m/s, A2 = 0.01m2. v2 = A1v1A2 = 0.02×20.01 = 4m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4 m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.