posted by k on .
The Venturi tube shown in the figure below may be used as a fluid flowmeter. Suppose the device is used at a service station to measure the flow rate of gasoline (ñ = 7.00 102 kg/m3) through a hose having an outlet radius of 2.72 cm. The difference in pressure is measured to be P1 − P2 = 2.00 kPa and the radius of the inlet tube to the meter is 1.36 cm.
(a) Find the speed of the gasoline as it leaves the hose.
(b) Find the fluid flow rate in cubic meters per second.
Try to use P2-P1 = ρ/2(v1^2-v2^2)
Derived from P1 + 1/2ρv1^2 = P2 + 1/2ρv2^2
Then A1V1 = A2V2 is from continuity and can be expressed V1 = A2V2/A1
You get the equation P2 - P1 = ρ/2((A2V2/A1)^2 - V2^2) via substitution
And then simplify to 2(P2-P1)/ρ = A2V2/A1 - V2^2
Plug in and solve