A horizontal pipe of cross-section diameter 5cm carries water at a speed of `4ms^(-1)`. The pipe is connected to a smaller pipe with a cross-sectional diameter 4cm. The velocity of water through the smaller pipe is

Options

A. `6.25 ms^(-1)`
B. `5.0 ms^(-1)`
C. `3.2 ms^(-1)`
D. `2.56 ms^(-1)`

Answer

A

Explanation

According to the equation of continuity, `A_(1)v_(1) = A_(1) v_(2)`
`:. V_(2) = v_(1) (A_(1))/(A_(2)) = v_(1) ((D_(1))/(D_(2)))^(2) = 4 xx ((5)/(4))^(2) = 6.25 ms^(-1)`