Question

Water is flowing at 6 m/s in a circular pipe.
If the diameter of the pipe decreases to five-seventh its former value, what is the velocity
of the water downstream?

Answer 1

assuming the same flow:

V1A1=V2A2

V2=6*A1/A2=6(7/5)^2 so flow changes inversly as the square of diameter change.

Answer 2

11.76