What law states that pressure at a point in a static liquid is equal in all directions?

The law that states that pressure at a point in a static liquid is equal in all directions is Pascal's Law. This principle, formulated by Blaise Pascal, asserts that when an external pressure is applied to a confined fluid at rest, that pressure change is transmitted undiminished throughout the fluid in every direction.

This means that if you increase the pressure in one part of the liquid, the same increase in pressure will occur instantly at all points in that liquid. This principle is crucial in various applications, including hydraulic systems, where force multiplication occurs due to the equal distribution of pressure. The uniformity of pressure in a fluid at rest helps in understanding fluid behavior in both engineering and natural environments.

Considerations about why other laws do not fit include: Archimedes' Principle, which focuses on buoyancy and the upward force exerted by a fluid, Boyle's Law, which pertains to the relationship between pressure and volume of gases, and Bernoulli's Principle, which relates to the conservation of energy in fluid flow and pressure changes with velocity. These principles address different aspects of fluid mechanics, making them unsuitable for describing the isotropic nature of pressure found in static liquids.