Which law underpins the operation of most hydraulic and pneumatic systems?

The operation of most hydraulic and pneumatic systems is primarily underpinned by Pascal's law. This principle states that when pressure is applied to a confined fluid, the pressure change occurs throughout the fluid equally and undiminished in all directions. In practical terms, this means that if you apply pressure to a fluid in a closed system, it will transmit that pressure uniformly throughout the system.

In hydraulic systems, this law allows for the multiplication of force, making it possible to lift heavy loads or power machinery by applying a relatively small force over a small area. For example, using a hydraulic press, a small amount of input pressure can result in a much larger output force, enabling the press to compress materials with great power.

In pneumatic systems, which operate using compressed air, Pascal's law similarly applies. The airflow and pressure generated in pneumatic systems enable various applications, such as powering tools or operating machinery, using the same foundational principle.

Considering the other principles, Newton's laws primarily describe motion and forces, but they do not specifically address fluid behavior in the same way that Pascal's law does. Bernoulli's principle relates to the speed of fluid movement and pressure changes along a streamline, and while important in fluid dynamics, it is not the fundamental principle