Below is a concise list of key definitions from Chapter 6: Fluid Dynamics

Below is a concise list of key definitions from Chapter 6: Fluid Dynamics of the 11th Class Physics syllabus for the Federal Board of Intermediate and Secondary Education (FBISE), aligned with the National Book Foundation (NBF) curriculum. These definitions cover the essential concepts related to fluid dynamics as typically presented in this chapter.

1. Fluid: A substance that can flow and take the shape of its container, including liquids and gases.
2. Fluid Dynamics: The branch of physics that studies the behavior of fluids in motion and the forces acting on them.
3. Density (ρ): The mass per unit volume of a fluid, given by ρ = m/V, measured in kg/m³.
4. Pressure (P): The force exerted per unit area by a fluid, given by P = F/A, measured in pascals (Pa).
5. Atmospheric Pressure: The pressure exerted by the Earth’s atmosphere, approximately 101,325 Pa at sea level.
6. Pascal’s Principle: The pressure applied to an enclosed fluid is transmitted undiminished to every part of the fluid and the walls of the container.
7. Hydraulic System: A system that uses an incompressible fluid to transmit force from one point to another, based on Pascal’s principle.
8. Viscosity: The internal resistance of a fluid to flow, caused by intermolecular friction, measured by the coefficient of viscosity (η) in pascal-seconds (Pa·s).
9. Streamline Flow: A smooth, orderly flow of a fluid in which fluid particles move in parallel paths without mixing.
10. Turbulent Flow: An irregular, chaotic flow of a fluid with eddies and vortices, occurring at high velocities or in complex systems.
11. Bernoulli’s Principle: For an ideal fluid in streamline flow, an increase in the fluid’s speed results in a decrease in its pressure, and vice versa.
12. Bernoulli’s Equation: A mathematical expression of Bernoulli’s principle, given by P + ½ρv² + ρgh = constant, where P is pressure, ρ is density, v is velocity, g is gravitational acceleration, and h is height.
13. Equation of Continuity: The principle that the mass flow rate of a fluid is constant in a steady flow, expressed as A₁v₁ = A₂v₂, where A is cross-sectional area and v is velocity.
14. Venturi Effect: The reduction in fluid pressure that occurs when a fluid flows through a constricted section of a pipe, as per Bernoulli’s principle.
15. Torricelli’s Theorem: The speed of a fluid exiting a small hole in a container is equal to the speed of a body falling freely from the height of the fluid surface to the hole, given by v = √(2gh).
16. Drag Force: The resistive force experienced by an object moving through a fluid, opposing its motion.
17. Terminal Velocity: The constant maximum velocity reached by an object falling through a fluid when the drag force equals the gravitational force.
18. Stokes’ Law: The drag force on a small spherical object moving slowly through a viscous fluid, given by F_d = 6πηrv, where η is viscosity, r is radius, and v is velocity.
19. Ideal Fluid: A theoretical fluid that is incompressible, non-viscous, and flows without turbulence.
20. Reynolds Number (Re): A dimensionless quantity that predicts whether fluid flow is laminar or turbulent, given by Re = ρvD/η, where ρ is density, v is velocity, D is diameter, and η is viscosity.

These definitions encapsulate the core concepts of fluid dynamics from Chapter 6 of the FBISE 11th Class Physics curriculum. If you need further explanation or additional terms, please let me know!