Work out continuity equation (flow) instantly with clear inputs, formula shown and shareable results.
For an incompressible fluid the volume passing every cross-section per second must be the same, so A1v1 = A2v2. Narrowing from 0.008 m2 to 0.002 m2 quadruples the speed from 2 to 8 m/s while the flow stays at 16 L/s. This is why a nozzle speeds up a hose and why river water races through a gorge.
Continuity
A1 x v1 = A2 x v2
Flow rate
Q = A x v
Only at low speed. Above about Mach 0.3 density changes and the mass form rho.A.v must be used instead.
Bernoulli's principle - the kinetic energy gained comes out of the pressure energy, which is what makes a venturi meter work.