AP Physics Study Packages AP Physics Fluids | Page 9

Bernoulli's Equation

Proof of Bernoulli's Equation

Daniel Bernoulli (1700-1782)–where the v of a fluid is high, P is low

and where v is low, P is high

The pressure at point 2 is lower (since v is greater @

point 2 than at point 1 where v is smaller). (a)

High pressure would slow the fluid down.

To derive Bernoulli’s equation, assume flow is steady and

laminar, the fluid is incompressible and viscosity is small enough

to be ignored.

P1 + ½ ρv12 + ρgy1 = P2 + ½ ρv22 + ρgy2

P1 + ½ ρv12 + ρgy1 = CONSTANT @ every point in the fluid

Bernoulli's equation is an expression of the law of energy

conservation since we derived it from the work-energy principle.