How Is the Throat's Cross-Sectional Area Determined Using Bernoulli's Principle?

[lnbanzon]

Homework Statement

air is flowing horizontally at a speed of 100 mph through a duct 4 square feet in cross section. the duct gradually narrows down to a throat section. if a U-tube shows a difference in pressure between the throat and main sections of 7 inch of water, what is the cross sectional area of the throat? (assume that the air is incompressible and has a density of 0.002378 slug per cubic feet)

Homework Equations

The Attempt at a Solution

i already have the final answer and it is

2.57 square/feet

but i need the solution... T_T.. help

Homework Statement

Homework Equations

The Attempt at a Solution

 

[rock.freak667]

For a horizontal pipe what is Bernoulli's equation reduced to?

When you get that formula you can find the velocity leaving the throat section.

Do you know the equation of continuity?