Physics 8

which answer is it then?

In 1 second a volume pi*(5^2/4)*2 cm^3 approaches the constriction.

In 1 second a volume pi*(3^2/4)*v cm3 leaves the constriction, where v is the speed

, in cm/s, of the water in the smaller pipe.

Equate the two volumes and rearrange to find v.

.

Solve for v:
(25 pi)/2 = (9 pi v)/4

(25 pi)/2 = (9 pi v)/4 is equivalent to (9 pi v)/4 = (25 pi)/2:
(9 pi v)/4 = (25 pi)/2

Divide both sides by (9 pi)/4:
Answer: | v = 50/9=5.56 cm/s. The answer is "D"