In a hydraulic system, applying pressure to confined fluid results in equal transmission in all directions, a principle known as

• A. Pascal's law
• B. Bernoulli's principle
• C. Archimedes' principle
• D. Boyle's law

Answer: (A)

Pascal's law states that when you apply pressure to a confined fluid, that pressure is transmitted equally in all directions and to every part of the fluid and the container. In a hydraulic system, pushing on a small-area piston creates a pressure P = F1/A1 that spreads throughout the fluid. This same pressure acts on the other piston, producing a force F2 = P × A2. If the second piston has a larger area, the output force F2 becomes greater than the input force F1, giving you a mechanical advantage. The trade-off is that the output piston must move farther or faster than the input piston to conserve energy (ignoring losses).

Other laws describe different situations: Bernoulli's principle deals with how speed and pressure trade off in moving fluids, not the equal transmission of pressure in a confined fluid; Archimedes' principle explains buoyant force on submerged objects; Boyle's law relates the pressure and volume of a gas at constant temperature.