Archimedes’ Principle

Archimedes of Syracuse is associated with foundational ideas in hydrostatics and mechanics. Two useful engineering principles are buoyancy and the balance of moments in a lever.

Buoyant force

An object immersed in a fluid experiences an upward force equal to the weight of the fluid it displaces: Fb = ρ × g × Vd. Here ρ is fluid density, g gravitational acceleration and Vd displaced volume. A floating object settles when buoyancy balances its weight.

Lever law

For an ideal lever in equilibrium, F1 × l1 = F2 × l2, where F is force and l is the perpendicular distance from the pivot. Real mechanisms also have friction, deformation and losses.