In fluid dynamics, steady flow is defined as a condition where fluid properties such as velocity, pressure, and density at a specific point do not change with respect to time. If these properties change over time, the flow is classified as unsteady. This concept is fundamental for analyzing hydraulic systems and irrigation networks.

Torsion is the twisting of an object due to an applied torque. Solids like steel, wood, and soil have shear strength and can resist or transmit torsional forces. Liquids, however, are fluids that deform continuously under shear stress and cannot support static torsional loads, as they lack the necessary structural rigidity.

In hydraulic engineering, the efficiency of a rectangular channel is determined by its geometry. For a given cross-sectional area and bed slope, the discharge is maximized when the hydraulic radius is optimized. Mathematically, for a rectangular section, this condition occurs when the depth of flow is exactly half of the channel width.

A hydraulic jump occurs when liquid at high velocity discharges into a zone of lower velocity, causing a sudden rise in the liquid surface level. This transition from supercritical to subcritical flow is commonly utilized in hydraulic structures, such as spillways and canals, to dissipate excess kinetic energy and prevent downstream erosion.

Uniform flow occurs when the velocity and cross-sectional area remain constant along the direction of flow. In such a scenario, the velocity vector is identical at all points along a streamline at a given instant, ensuring that the flow characteristics do not change with respect to space.

Power is calculated as the product of force and velocity or the rate of work done. Here, Power = Force × Height / Time. Given Force/Time = 100 N/sec and Height = 100 m, Power = 100 * 100 = 10,000 Watts. Note: The provided answer 10,000 kw appears to be a unit error in the source, as the calculation yields 10,000 Watts (10 kW).

Specific heat capacity is defined as the amount of heat required to change the temperature of a unit mass of a substance by one degree. It is a fundamental physical property that determines how materials respond to thermal energy. In agricultural contexts, understanding the specific heat of soil and water is crucial for managing irrigation and predicting microclimate changes in crop fields.

A piezometer is a simple device consisting of a tube open to the atmosphere at one end and connected to the fluid container at the other. The height of the liquid column in the tube represents the pressure above atmospheric pressure, which is defined as gauge pressure. It is not suitable for measuring vacuum or absolute pressure directly without modification.

Surface tension is the property of a liquid surface that allows it to resist an external force, caused by the cohesion of liquid molecules. Because a sphere has the smallest surface area for a given volume, surface tension forces pull the water molecules inward, causing the droplet to minimize its surface area and adopt a spherical shape while falling through the air.

Stokes' Law describes the drag force exerted on spherical objects moving through a viscous fluid. It is valid only for laminar flow conditions where inertial forces are negligible compared to viscous forces. This condition is generally satisfied when the Reynolds number is very low, typically defined as being less than or equal to 0.2 to 2 depending on the precision required.