Question

An ideal fluid flows through a long horizontal circular pipe. In one region of the pipe, it has radius R. The pipe then widens to radius 2R. What is the ratio of the fluids speed in the region of radius R to the speed of the fluid in region with radius 2R 

(A) ¼ 

(B) ½ 

(C) 1 

(D) 2 

(E) 4 

Answer 1

Correct option (E) 4

Using fluid continuity. A₁v₁ = A₂v₂

πR²v₁ = π(2R)² v₂

v₁ = 4v₂