An incompressible fluid flows steadily through a cylinder pipe which has radius 2 R at point A and radius R at point B further along the flow direction. IF the velocity at point A is v, its velocity at a point B will be

Options

A. 2 v
B. v
C. v/2
D. 4v

Answer

D

Explanation

`A_(1)V_(1) = A_(2)V_(2), 4 pi (2R)^(2) V = 4piR^(2) V _(1), V_(1) = 4V`