Posted by Henry on .
A 6.0cm diameter horizontal pipe gradually narrows to 4.0 cm. When water flows through this pipe at a certain rate, the gauge pressure in these two sections is 32 kPa and 24 kPa, respectively. What is the volume rate of flow?
I know to use Bernoulli's Equation and the Equation of Continuity, but I can't figure out how to solve for either velocity variable.

AP Physics  Fluids 
drwls,
P1  P2 = (rho/2)(V2^2  V1^2)= 8000 N/m^2 (Bernoulli equation)
(rho is the fluid density)
6^2*V1 = 4^2*V2, so V2 = (4/9)V1
(from the continuity equation)
Substitute (4/9)V1 for V2 in the first equation and solve for V1
The volume flow rate is (pi/4)D^2*V1
where D = 0.06 m 
AP Physics  Fluids 
Anonymous,
horrible