What does Pascal's principle state in fluid mechanics?

Pascal's principle, also known as Pascal's law, states that a change in pressure applied to an enclosed fluid is transmitted undiminished throughout the fluid. This is a fundamental concept in fluid mechanics that explains how hydraulic systems operate, where force applied at one point can be transmitted to another point within the fluid system, thereby amplifying the force.

The principle emphasizes that if pressure is applied at any point in a confined fluid, all parts of the fluid experience the same increase in pressure. This characteristic is what enables devices such as hydraulic lifts and brakes to function effectively, allowing a small input force to produce a much larger output force through the uniform transmission of pressure across the fluid.

In contrast, the other choices address related concepts but do not accurately encapsulate the essence of Pascal's principle. While it is true that pressure can vary in different parts of a fluid under certain conditions, Pascal's principle specifically applies to a uniform transmission of pressure changes in static fluids. The assertion that pressure decreases with depth pertains to hydrostatic pressure, and stating that a change in pressure is absorbed by the fluid does not reflect the immediate response of pressure transmission that Pascal's law describes.