What happens to a flexible hose under pressure in a hydraulic system?

In a hydraulic system, when pressure is applied to a flexible hose, the hose material behaves in a particular way due to the principles of fluid mechanics and material science. The correct understanding is that as pressure increases within the hose, it generally contracts in length while expanding in diameter. This phenomenon occurs because the materials that make up the hose are designed to withstand pressure but will still exhibit some degree of elastic deformation.

When the fluid pressure is applied, the internal force pushes outward against the walls of the hose, leading to a bulging effect that causes the diameter to increase. Simultaneously, the confined nature of the hose restricts its potential to expand in length, which results in the observed contraction in that dimension.

This behavior is critical for understanding the limits of hose performance under pressure, including safe working pressures and potential failure points, thus making it essential knowledge for operators in hydraulic systems. The other choices do not accurately describe the physical behavior of flexible hoses under pressure, as they misrepresent how the geometry of the hose responds to hydraulic forces.