Answer:
Pressure:
Pressure is a physical quantity that describes the force exerted per unit area on a surface. It is defined as the force applied perpendicular to the surface divided by the area over which the force is applied. Mathematically, pressure (P) can be expressed as P = F/A, where F is the force and A is the area. The SI unit of pressure is the pascal (Pa), which is equal to one newton per square meter (N/m²). Pressure is a crucial concept in fluid mechanics and is used to understand various phenomena, such as fluid flow, buoyancy, and atmospheric pressure.
Fluid Friction:
Fluid friction, also known as viscous drag or simply viscosity, is a resistance force experienced by a fluid (liquid or gas) when it flows past a solid surface or another fluid layer. It arises due to the internal friction within the fluid itself as its molecules slide past each other. Fluid friction is influenced by factors such as the viscosity of the fluid and the relative velocity between the fluid and the solid surface. The higher the viscosity of the fluid and the faster the flow, the greater the fluid friction. Fluid friction plays a significant role in various applications, including the design of efficient transportation systems, lubrication in machinery, and understanding the behavior of fluids in different environments.