lesson

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When you step gently on a car's brake pedal, your foot exerts barely enough force to squash a soda can β yet it instantly stops a 4,000-pound vehicle traveling at highway speed.
To see how fluids magnify your strength, we start with pressure, which measures how much force is spread across a surface: P=AFβ, where F is force in newtons (N) and A is surface area in square meters (m2).
πInteractive diagram
What happens when that pressure isn't pushing on an open floor, but on a trapped liquid inside sealed pipes?
Pascal's Principle
In 1653, French scientist Blaise Pascal discovered that any change in pressure applied to a completely enclosed, stationary fluid transmits equally in all directions throughout the entire fluid.
Because liquids like oil and water are essentially incompressible (their volume cannot be squeezed smaller), the fluid cannot absorb the squeeze β it simply pushes against every square millimeter of its container with identical pressure.
πInteractive diagram
Because the pressure at the input piston (P1β) must equal the pressure at the output piston (P2β), we can set their pressure ratios equal to each other.
A1βF1ββ=A2βF2βββΉF2β=F1ββ
(A1βA2ββ)
If the output area A2β is 10 times bigger than the input area A1β, the output force F2β is automatically multiplied by 10.
How do we put this formula to work in a real garage lift?